The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 76

I get asked a lot about how mast cell disease can affect common blood test results. I have broken this question up into several more manageable pieces so I can thoroughly discuss the reasons for this. The next few 107 series posts will cover how mast cell disease can affect red blood cell count; white blood cell count, including the counts of specific types of white blood cells; platelet counts; liver function tests; kidney function tests; electrolytes; clotting tests; and a few miscellaneous tests.

89. How does mast cell disease affect platelet counts?

Before I continue, I want to explain one basic fact. Even though they are often included in the term “blood cells”, platelets are not actually cells. They are actually pieces of an original large cell called a megakaryocyte that lives in the bone marrow. Even though platelets are not really cells, they more or less act like they are.

An unusual thing about platelets is that sometimes a specific trigger can cause platelets to become lower or higher.

There are several ways in which mast cell disease can make platelet counts lower.

  • Swelling of the spleen. This can happen in some forms of systemic mastocytosis, and may also happen in some patients with mast cell activation syndrome, although the reason why it happens in MCAS is not as clear. Swelling of the spleen can damage blood cells and platelets, causing lower platelet counts. If the spleen is very stressed and working much too hard, a condition called hypersplenism, the damage to blood cells and platelets is much more pronounced. This may further lower platelet counts. Hypersplenism occurs in aggressive systemic mastocytosis or mast cell leukemia. It is not a feature of other forms of systemic mastocytosis and I am not aware of any cases as a result of mast cell activation syndrome.
  • Medications. Some medications that are used to manage mast cell disease can cause low red blood cell count. Chemotherapies, including targeted chemotherapies like tyrosine kinase inhibitors, can cause low platelet counts. Non steroidal anti-inflammatory drugs (NSAIDs) are used by some mast cell patients to decrease production of prostaglandins. They can interfere with platelet production in the bone marrow. Proton pump inhibitors, often used by mast cell patients to help with GI symptoms like heart burn, can decrease platelet coun Some H2 antihistamines can also lower platelet production. However, none of these H2 antihistamines are currently used in medicine.
  • Heparin induced thrombocytopenia. Mast cells make and release large amounts of heparin, a powerful blood thinner. When there is an excessive amount of heparin circulating, it can cause your body to incorrectly produce antibodies that cause an immune response to heparin. A side effect of this situation is that platelets are activated incorrectly, which can lead to the formation of blood clots and low platelet counts. Heparin induced thrombocytopenia has only been definitively described in patients who receive medicinal heparin as a blood thinner. However, it is reasonable to assume that this situation can also affect mast cell patients who have higher than normal levels of platelets circulating in the blood.
  • Liver damage. Liver damage is associated with malignant forms of systemic mastocytosis such as aggressive systemic mastocytosis and mast cell leukemia. Liver damage can also occur as the result of IV nutrition, which is sometimes needed by patients with mastocytosis or mast cell activation syndrome. When the liver is damaged enough, it may not make enough of the molecules that tell the bone marrow to make platelets.
  • Excessive production of blood cells. In very aggressive forms of systemic mastocytosis, aggressive systemic mastocytosis or mast cell leukemia, the bone marrow is making huge amounts of mast cells. As a result, the bone marrow makes fewer platelets and cells of other types.
  • Vitamin and mineral deficiencies. Chronic inflammation can affect the way your body absorbs vitamins and minerals through the GI tract, and the way it uses vitamins and minerals that it does absorb. Deficiency of vitamin B12 or folate can decrease platelet production.
  • Excess fluid in the bloodstream (hypervolemia). In this situation, the body doesn’t actually have too few platelets, it just looks like it. If your body loses a lot of fluid to swelling (third spacing) and that fluid is mostly reabsorbed at once, the extra fluid in the bloodstream can make it look like there are too few platelets if they do a blood test. This can also happen if a patient receives a lot of IV fluids.

There are also reasons why mast cell disease can cause the body to make too many platelets.

  • Anemia of chronic inflammation. This is when chronic inflammation in the body affects the way the body absorbs and uses iron. It can result in iron deficiency. Iron deficiency can increase platelet counts.
  • Hemolytic anemia. In hemolytic anemia, the body destroys red blood cells. This can happen for several reasons that may be present in mast cell patients. Hemolytic anemia can increase platelet counts.
  • Iron deficiency. Iron deficiency for any reason can elevate platelet counts.
  • Excessive bleeding. Mast cell disease can cause excessive bleeding in several ways. Mast cells release lots of heparin, a very potent blood thinner that decreases clotting. This makes it easier for the body to bleed. It is not unusual for mast cell patients to have unusual bruising. Bleeding in the GI tract can also occur. Mast cell disease can cause ulceration, fissures, and hemorrhoids, among other things. Mast cell disease can contribute to dysregulation of the menstrual cycle, causing excessive bleeding in this way. It is not unusual for mast cell patients to have GI bleeding, as well as ulceration, fissures, and hemorrhoids.
  • Sustained GI inflammation. Sustained GI inflammatory disease can cause elevated levels of platelets. Given what we know about mast cell driven GI inflammation, it is reasonable to infer that mast cell GI effects and damage may also elevate platelet levels.
  • Clot formation. If a large clot forms, it can affect the amount of platelets circulating in the blood. Some mast cell patients require central lines for regular use of IV therapies or to preserve IV access in the event of an emergency. Blood clots can form on the outside surface of the line, inside the line, or between the line and the wall of the blood vessel it is in.
  • General inflammation. Platelets are activated by a variety of molecules released when the body is inflamed for any reason. This can translate to increased levels of platelet production.
  • Allergic reactions. Platelets can be directly activated by mast cell degranulation through molecules like platelet activating factor (PAF).
  • Heparin. Heparin can cause platelet levels to increase. As I mentioned above, it can also cause platelet levels to decrease.
  • Removal of the spleen. The spleen can become very stressed and work too hard, a condition called This situation is remedied by removing the spleen. Hypersplenism occurs in aggressive systemic mastocytosis or mast cell leukemia. It is not a feature of other forms of systemic mastocytosis and I am not aware of any cases as a result of mast cell activation syndrome.
  • Glucocorticoids. In particular, prednisone is known to increase platelet counts. Prednisone and other glucocorticoids can be used for several reasons in mast cell patients.
  • Third spacing. If a lot of fluid from the bloodstream becomes trapped in tissues (third spacing), there is less fluid in the bloodstream so it makes it look like there are too many cells. As I mentioned above, this is not really a scenario where you are making too many red blood cells, it just looks like that on a blood test.

For additional reading, please visit the following posts:

Anemia of chronic inflammation

Effect of anemia on mast cells

Mast cell disease and the spleen

MCAS: Anemia and deficiencies

Mast cells, heparin and bradykinin: The effects of mast cells on the kinin-kallikrein system

MCAS: Blood, bone marrow and clotting

Third spacing

Gastrointestinal manifestations of SM: Part 1

Gastrointestinal manifestations of SM: Part 2

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 72

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 73

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 74

I get asked a lot about how mast cell disease can affect common blood test results. I have broken this question up into several more manageable pieces so I can thoroughly discuss the reasons for this. The next few 107 series posts will cover how mast cell disease can affect red blood cell count; white blood cell count, including the counts of specific types of white blood cells; platelet counts; liver function tests; kidney function tests; electrolytes; clotting tests; and a few miscellaneous tests.

  1. How does mast cell disease affect red blood cell counts?

There are several ways in which mast cell disease can make red blood cell count lower.

  • Anemia of chronic inflammation. This is when chronic inflammation in the body affects the way the body absorbs and uses iron. It can result in iron deficiency. Iron is used to make hemoglobin, the molecule used by red blood cells to carry around oxygen to all the places in the body that need it. If there’s not enough iron to make hemoglobin, the body will not make a normal amount of red blood cells.
  • Vitamin and mineral deficiencies. Like I mentioned above, chronic inflammation can affect the way your body absorbs vitamins and minerals through the GI tract, and the way it uses vitamins and minerals that it does absorb. While iron deficiency is the most obvious example of this, deficiency of vitamin B12 or folate can also slow red cell production.
  • Swelling of the spleen. This can happen in some forms of systemic mastocytosis, and may also happen in some patients with mast cell activation syndrome, although the reason why it happens in MCAS is not as clear. Swelling of the spleen can damage blood cells, including red blood cells, causing lower red blood cell counts. If the spleen is very stressed and working much too hard, a condition called hypersplenism, the damage to blood cells is much more pronounced. This may further lower the red blood cell count. Hypersplenism occurs in aggressive systemic mastocytosis or mast cell leukemia. It is not a feature of other forms of systemic mastocytosis and I am not aware of any cases as a result of mast cell activation syndrome.
  • Medications. Some medications that are used to manage mast cell disease can cause low red blood cell count. Chemotherapies, including targeted chemotherapies like tyrosine kinase inhibitors, can cause low red blood cell count. Medications that specifically interfere with the immune system can do the same thing, including medications for autoimmune diseases like mycophenolate. Non steroidal anti-inflammatory drugs (NSAIDs) are used by some mast cell patients to decrease production of prostaglandins. They can interfere with red blood cell production in the bone marrow and also cause hemolytic anemia, when the immune system attacks red blood cells after they are made and damages them.
  • Excessive bleeding. Mast cell disease can cause excessive bleeding in several ways. Mast cells release lots of heparin, a very potent blood thinner that decreases clotting. This makes it easier for the body to bleed. It is not unusual for mast cell patients to have unusual bruising. Bleeding in the GI tract can also occur. Mast cell disease can cause ulceration, fissures, and hemorrhoids, among other things. Mast cell disease can contribute to dysregulation of the menstrual cycle, causing excessive bleeding in this way.
  • Excessive production of other types of blood cells. In very aggressive forms of systemic mastocytosis, aggressive systemic mastocytosis or mast cell leukemia, the bone marrow is making huge amounts of mast cells. As a result, the bone marrow makes fewer cells of other types, including red blood cells. Some medications can also increase production of other blood types, causing less production of red cells. Corticosteroids can do this.
  • Excess fluid in the bloodstream (hypervolemia). In this situation, the body doesn’t actually have too few red blood cells, it just looks like it. If your body loses a lot of fluid to swelling (third spacing) and that fluid is mostly reabsorbed at once, the extra fluid in the bloodstream can make it look like there are too few red cells if they do a blood test. This can also happen if a patient receives a lot of IV fluids.

There are also a couple of scenarios where mast cell disease can make the red blood cell count higher. This is much less common.

  • Chronically low oxygen. If a person is not getting enough oxygen for a long period of time, the body will make more red blood cells in an effort to compensate for the low oxygen. This could happen in mast cell patients with poor oxygenation.
  • Third spacing. If a lot of fluid from the bloodstream becomes trapped in tissues (third spacing), there is less fluid in the bloodstream so it makes it look like there are too many cells. As I mentioned above, this is not really a scenario where you are making too many red blood cells, it just looks like that on a blood test.

For additional reading, please visit the following posts:

Anemia of chronic inflammation

Effect of anemia on mast cells

Effects of estrogen and progesterone and the role of mast cells in pregnancy

Explain the tests: Complete blood cell count (CBC) – Low red cell count

Explain the tests: Complete blood cell count (CBC) – High red cell count

Explain the tests: Complete blood cell count (CBC) – Red cell indices

Gastrointestinal manifestations of SM: Part 1

Gastrointestinal manifestations of SM: Part 2

Mast cell disease and the spleen

Mast cells, heparin and bradykinin: The effects of mast cells on the kinin-kallikrein system

MCAS: Anemia and deficiencies

MCAS: Blood, bone marrow and clotting

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 3

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 12

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 19

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 20

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 45

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 72

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 73

Third spacing

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 69

83. Are there any supplements that help manage mast cell symptoms?

  • Yes.
  • Mast cell patients are often vitamin or mineral deficient.
  • Iron deficiency is extremely common. This is likely due to anemia of chronic inflammation. Basically, if your body is inflamed long enough, your body hoards the iron and stops moving it from your GI tract into your bloodstream where it can be used. Iron supplements are pretty harsh so patients don’t always tolerate oral supplements. IV iron is an option if your iron is low enough. I personally like the Lucky Iron Fish for increasing iron. It’s pretty neat.
  • Many mast cell patients are magnesium deficient. The exact cause of this is unknown. Lots of us take magnesium supplements.
  • For reasons that aren’t clear, a lot of mast cell patients are vitamin D deficient. Vitamin D acts on mast cells. There is some evidence to suggest that vitamin D can decrease mast cell activation. I personally found that effectively supplementing vitamin D has helped me a lot. A lot of symptoms I blamed on mast cell disease were actually vitamin D deficiency.
  • A number of supplements can decrease mast cell activation or block the action of mast cell mediators. There are a ton of natural mast cell stabilizers. They are sometimes used to help patients manage symptoms, especially in Traditional Chinese Medicine, which in recent years has been studied in clinical trials. Quercetin and resveratrol are commonly used by mast cell patients.
  • I take turmeric daily to reduce inflammation. Turmeric or curcumin can decrease prostaglandin production.
  • Holy Basil is a popular supplement in the mast cell community. It also decreases prostaglandin production. It can also block the histamine H2 receptor. While I often see people say that holy basil is as effective as an H2 blocker as H2 antihistamines like ranitidine or famotidine, I have never been able to find any evidence that this is true. But it does definitely have some ability to block the histamine H2 receptor.
  • Vitamin B12 deficiency sometimes occurs in mast cell patients, especially those with mast cell activation syndrome. This can have some interplay with MTHFR mutations, which can affect the form of vitamin B12 best suited to your body.
  • Vitamin C decreases the amount of histamine released by mast cells. It is recommended by some prominent mast cell researchers and many patients respond well.
  • Alpha lipoic acid is sometimes used, particularly for neurologic symptoms and neurologic pain.
  • I’m not sure if CBD oil is considered a supplement but it is widely used with excellent results. Be aware that the popular notion that marijuana derivatives do not interact with any medications is inaccurate. It especially can interact with tricyclic antidepressants to cause dangerous tachycardia.
  • Keep in mind that all supplements have the potential to interact with medications or to affect a person adversely if they have certain diseases. Exactly how much this happens is hard to pinpoint because over the counter supplements are held to a much lower standard for this type of study than FDA approved medications.
  • Always discuss any supplements you plan to try with your managing provider. Vitamins and minerals can cause toxicity and too much can cause very serious side effects and complications.
  • Do not assume that just because something is derived from nature, or because it is available without a prescription, that something is automatically safer for you than medications.
  • This is not really in my wheelhouse so I would encourage you to ask other patients what has helped them or to consult with a nutritionist.

For additional reading, please visit the following posts:

Effect of vitamin D on mast cells
Naturally occurring mast cell stabilizers: Part 1
Naturally occurring mast cell stabilizers: Part 2
Naturally occurring mast cell stabilizers: Part 3
Naturally occurring mast cell stabilizers: Part 4
The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 19
MTHFR, folate metabolism and methylation

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 19

I answered the 107 questions I have been asked most in the last four years. No jargon. No terminology. Just answers.

28. Why are so many mast cell patients anemic?
• Anemia occurs when a person has too few red blood cells or not enough hemoglobin. Red blood cells are essentially envelopes that serve specifically to hold hemoglobin. Hemoglobin is a molecule made with iron that picks up oxygen. When you have either too few red blood cells or they don’t have enough hemoglobin, not enough oxygen gets to all the parts of the body that need it.
Patients with chronic illness of many kinds often have anemia. This is called anemia of chronic inflammation or anemia of inflammatory response.
• This type of anemia occurs because of the overactivity of a hormone called hepcidin. This hormone tells cells in the GI tract to hold onto any iron they find. This means they do not pass the iron along to the blood so it can make hemoglobin. Since the body isn’t making enough hemoglobin, the body doesn’t get enough oxygen.
• Mast cell patients often have anemia of chronic inflammation so they may be anemic regardless of how much iron they have in their diet. However, increased supplementation sometimes helps.
• There are several forms of iron that can be taken by mouth. IV iron is also an option. Some people have luck cooking in cast iron pans or using the “Lucky Iron Fish” to get even more iron into their diet in hopes that they can take up a little bit more.
Having enough iron available also decreases mast cell activation. Mast cells make smaller amounts of inflammatory molecules when the body has sufficient iron.
• Mast cell patients may also selectively malabsorb iron in their GI tracts. This means that even if they are absorbing enough of other nutrients, they may not absorb enough iron properly due to inflammation. This sometimes improves with antihistamines.
• Mast cell patients usually take histamine H2 blockers. This decreases the strength of stomach acid which can affect absorption of nutrients like iron. Taking PPIs can do the same thing.
• Malabsorption of other nutrients, like copper, can contribute to anemia.
• Insufficient amounts of B12 or folate can cause also contribute to anemia.

For more detailed reading, please visit these posts:
Anemia of chronic inflammation
MCAS: Anemia and deficiencies
Effect of anemia on mast cells

Take home points: November 2015

Immunoglobulin free light chains: A possible link between autoimmune disease and mast cell activation

  • Light chains are part of antibodies that fight infections and responds to allergens
  • Free light chains are pieces of antibodies that broke off and do not work as antibodies
  • Elevation of immunoglobulin free light chains has been linked to many diseases, including lupus, rheumatoid arthritis, inflammatory bowel disease and food allergy
  • Free light chains correlate with symptom severity and flares in some conditions
  • Free light chains may be able to activate mast cells without IgE involvement
  • Free light chains may be the link between mast cell activation and autoimmune disease

Explain the tests: Complete blood count (CB) with differential and platelets (Part One)

  • A complete blood count (CBC) counts white blood cells, red blood cells and platelets in blood
  • It also looks at the shape, size and variation in size of cells

Explain the tests: Complete blood count (CBC) – Low red cell count (Part two)

  • Mature red blood cells live in the blood for 100-120 days
  • Hemolysis is when red blood cells burst and a little bit of hemolysis is normal
  • Red blood cells transport oxygen from lungs to tissues
  • Red blood cells have hemoglobin inside them
  • Hemoglobin is a protein with iron in the middle and it carries oxygen
  • Low red blood cell count or hemoglobin is called anemia
  • Red blood cell count can be low for several reasons, including nutritional deficiency and production dysregulation in bone marrow
  • Mast cell patients often suffer from anemia of chronic inflammation, which can cause low red count
  • Patients with inflammatory bowel disease can have low red count due to bleeding
  • Swelling of spleen can cause low red count

Explain the tests: Complete blood count (CBC) – Low red cell count (Part two)

The process of making red blood cells is called erythropoiesis.  Mature red cells live in the blood for 100-120 days before they die.  As they get older, red cells are removed from the blood stream.  A small amount of red cells burst in the blood stream before they are removed.  This is called hemolysis.  Most red cells are removed by special white cells called macrophages in the liver, spleen and lymph nodes.  When the production and destruction of red cells are not balanced, red cell count is abnormal.

Red blood cells (erythrocytes) are responsible for transporting oxygen from the lungs to the tissues.  Red blood cells have lots of hemoglobin inside their cells.  Hemoglobin is a protein that has a form of iron at its center called heme.  Hemoglobin binds oxygen so that it can be brought to other parts of the body.  When red blood cell count or hemoglobin is low, the body cannot get enough oxygen to the tissues.  This is called anemia.

A number of conditions can cause low red blood cell count.  They can be placed into three categories: not making enough red blood cells; breaking down too many red blood cells; and blood loss.  Additionally, changes in amount of fluid in the blood stream can artificially alter red blood cell and hemoglobin levels.

Normal range for red blood count:

  • Adult women: 3.9-5.0 million cells/µL
  • Adult men: 4.3-5.7 million cells/µL

Reasons for not making enough red blood cells:

  • Low levels of erythropoietin, a molecule that tells the bone marrow to make red cells
  • Deficiency or abnormality of hemoglobin
  • Nutritional deficiency
  • Damage to stem cells
  • Inability to make red cells from stem cells

Some conditions that interfere with making enough red blood cells:

  • Viral infections, such as parvovirus B19, herpes viruses and hepatitis. Some viruses induce pure red cell aplasia, which affects the cells that become red blood cells.
  • Overproliferation of white cells, such as lymphomas, leukemias, autoimmune lymphoproliferative disease. These conditions can also induce pure red cell aplasia. If too many of one cell type is in the bone marrow, it reduces the space for other cell types.  In this example, too many white cells are produced, so there is not enough space for red cells.
  • Myelodysplastic syndromes. In MDS, the stem cells that develop into blood cells are thought to harbor damaging mutations.  The process of making blood cells is very disordered in MDS.
  • Aplastic anemia. In aplastic anemia, blood stem cells are damaged.
  • Deficiency of vitamin B12, iron or folate. Iron deficiency interferes with production of hemoglobin, while B12 or folate deficiency prevents normal cell division to make new cells.
  • Chronic kidney disease. Kidney cells release erythropoietin to stimulate making new red cells.  If the kidney cells are damaged, they may release less erythropoietin.
  • Chronic inflammation. Chronic inflammation can interfere with absorption and use of iron.
  • Thalassemia causes hemoglobin to be misshapen.
  • Medications, like mycophenolate.

Reasons for increased destruction of red cells

  • Misshapen red cells
  • Abnormalities of red cell membranes
  • Hemoglobinopathies, conditions in which hemoglobin is defective
  • Attack by antibodies
  • Mechanical damage

Some conditions that cause increased destruction of red cells:

  • Hemolytic anemias. This is a general category that encompasses many conditions, including antibody mediated hemolysis, enzyme deficiencies and membrane abnormalities.
  • Membrane abnormalities, like in G6PD deficiency (favism). The membrane is weakened in this condition.
  • Hereditary spherocytosis and hereditary elliptocytosis. In these genetic conditions, red cells are misshapen.
  • Antibodies targeting red cells, such as autoimmune hemolytic anemia and transfusion reaction.
  • Hemoglobinopathies, like sickle cell disease and hemoglobin C disease. Enough hemoglobin is made, but it is structurally abnormal.
  • In this condition, there is a genetic mutation that interferes with production of hemoglobin.
  • Mechanical damage, such as in hemodialysis or malaria. In these conditions, the red cells die for physical reasons.

Reasons for blood loss

  • Trauma or surgery.
  • Gastrointestinal bleeding. This can be caused by inflammatory bowel disease, ulceration, varices or infection.
  • Excess blood loss due to menstruation or fibroids
  • Anemia of prematurity. This is caused by the need for frequent blood draws for testing coupled with low production of red cells by premature babies.

Situations that cause artificially low red blood cell count:

  • Pregnancy, due to increased blood volume.
  • Hypervolemia, from high water or sodium consumption or retention.
  • Hypervolemia, from recovery of third spaced fluids.

 

Special notes on low red cell count for mast cell patients:

  • Many mast cell patients suffer from anemia of chronic inflammation, which can result in low red cell count.
  • Some patients have inflammatory bowel disease, which can result in low red cell count.
  • Swelling of the spleen (splenomegaly) can cause low red cell count.  Splenomegaly is a B finding for SM patients.  Two B findings result in diagnosis with smoldering systemic mastocytosis (SSM).
  • Overactivity of the spleen (hypersplenism) can cause low red cell count.  Hypersplenism is a C finding for SM patients, resulting in diagnosis with aggressive systemic mastocytosis (ASM).
  • Use of some chemotherapy drugs can impair production of blood cells, including red cells.

 

MCAS: Anemia and deficiencies

Anemia is the most common issue affecting red blood cells in MCAS patients.  It can be macrocytic (big cells), normocytic (normal size), or microcytic.  Usually mild to moderate, but occasionally the diagnosis is mistaken for pure red cell aplasia on bone marrow examination.  When macrocytosis is predominant, BMB must be performed to rule out myelodysplastic syndrome (MDS.) 
Cobalamin deficiency is common, even when pernicious anemia is ruled out.  Copper deficiency is sometimes the cause for microcytic anemia, although in MCAS, it sometimes causes normocytic or macrocytic anemia.  This may be caused by absorption, but is also a side effect of overdose of zinc, a common ingredient in over the counter medications taken by MCAS patients to reduce symptoms. Folate deficiency is less frequently found in MCAS and is often due to hemolysis from an acquired condition like acquired chronic autoimmune hemolytic anemia, sometimes found to occur secondary to mast cell disease.  Other hemolytic conditions, like paroxysmal nocturnal hematouria, should be ruled out.
Many MCAS patients have selective iron malabsorption, which sometimes resolves with antihistamine treatment.  GI bleeds must be excluded.  Oral iron absorption tests can be done to test iron malabsorption.  A recent procedure calls for a blood sample to establish baseline plasma iron, administration of 100mg dose of oral sodium ferrous citrate, and another blood sample to test plasma iron two hours later.  Increase of less than 50 ug/dl is considered evidence of malabsorption.
Iron malabsorption can happen for several reasons in the context of MCAS.  Iron deficiency can be from MCAS immune dysfunction that leads to generation of antibodies against the acid secreting cells of the stomach.  When the concentration of stomach acid is too low (achlorhydria), the absorption of non heme dietary iron is dramatically reduced.   H2 antihistamines and PPI medications can interfere with iron absorpotion.   Hepcidin, the production of which is stimulated by mast cell mediators like IL-6 and TNFa, slows down the rate with which GI cells transfer the iron into the blood stream for use.
MCAS patients sometimes exhibit low serum iron and ferritin, but have normal MCV and RCDW, which indicates no deficiency is present.  This profile is thought to allude to correct transport of iron to the blood stream but poor utilization in the bone marrow. 

References:
Afrin, Lawrence B. Presentation, diagnosis and management of mast cell activation syndrome.  2013.  Mast cells.
Kobune M, et al.  Establishment of a simple test for iron absorption from the gastrointestinal tract.  Int. J. hematol. 2011; 93:715-719.
Hitchinson C, et al. Proton pump inhibitors suppress absorption of dietary non-haem iron in hereditary hemochromatosis.  Gut 2007 Sep; 56(9):1291-1295.

Effect of anemia on mast cells

A paper released in September 2012 addressed the effect of iron availability on mast cell degranulation.
Inside the bodies of mice, it was observed that mice with decreased iron stores had more severe inflammatory reactions.  Importantly, iron supplementation decreased the severity of the inflammation, particularly in the context of allergic asthma.  Increased iron inhibited the production of inflammatory molecules in pulmonary tissues, including various interleukins and interferons. 
Outside of the body, mast cells were incubated with and without iron for 30 minutes.  IgE was then added to activate the mast cells.  The mast cells that were incubated with iron degranulated 30% less than those without iron present.  Spontaneous degranulation, without IgE crosslinking, was not affected.  The presence of iron also dramatically affected the production of inflammatory molecules by mast cells.  Production of TNF, MCP-1 and IL-6 decreased by 94%, 29% and 27%, respectively.  MCP-1 attracts macrophages. 
Iron supplementation decreased the severity of allergic asthma, and decreased mast cell degranulation by IgE crosslinking 30%, as well as decreasing production of inflammatory molecules by mast cells.

Reference:
Hale LP, Kant EP, Greer PK, Foster WM (2012) Iron Supplementation Decreases Severity of Allergic Inflammation in Murine Lung. PLoS ONE 7(9): e45667. doi:10.1371/journal.pone.0045667

Anemia of chronic inflammation

Anemia is the condition of having either too few red blood cells or too little hemoglobin.  Hemoglobin is a protein found in red blood cells that transports oxygen.  Hemoglobin is one of the hemeproteins, meaning that it has an iron atom in the middle of a structural ring.  The iron allows hemoglobin to transport oxygen from the lungs to the capillaries, small blood vessels.  Thus, anemia can result in less than enough oxygen in the organs.  Iron status (how much iron a person has available for use) affects how well the body can oxygenate the tissues and generate energy.

Anemia is fairly common.  It is generally caused by blood loss, destroying too many blood cells (hemolysis) or not diminished hematopoiesis (the process of making red blood cells.)  Typical symptoms include weakness, fatigue, palness and shortness of breath.  More serious cases can cause heart palpitations, chest pain, fast heart rate and even heart failure.    There are many types of anemia.
One type of anemia is anemia of chronic disease, also called anemia of inflammatory response.  This type of anemia is seen in chronic illness.  In recent years, we have learned that this is most likely caused by overactivity of hepcidin, a hormone.  Hepcidin is the chief controller of iron levels in the body.  It can slow the body taking up iron from the diet and prevent iron from being released from its stores.
Overloading with iron will activate the body to make hepcidin.  This will result in a decrease in available iron, an increase of iron inside the cells that store it, and decreased absorption of iron in the gut.  Iron stores are composed mostly of cells in the reticuloendothelial system (RES), an older name for the mononuclear phagocyte system (MPS.)  These are cells that “eat” disease causing organisms, damaged cells or cellular debris, like macrophages.  Some of the cellular debris is pieces left over from broken down red blood cells, including heme.  Your body stores excess iron inside these cells to save for a time when it is needed. 
Your hepcidin level is regulated in response to many things, including anemia and inflammation.  Acute hemolysis, or destruction of red blood cells, from repeated blood draws decreased the amount of hepcidin your body made, even if the level was very high before.  This means that having blood drawn frequently signals to the body that it needs to keep its iron in its stores and shouldn’t take up any more from your diet.   
Acute inflammation decreases hepcidin, making iron more available.  But chronic inflammation increases hepcidin over 6X, making iron much less available to your body.  When your body is inflamed, its cells produce inflammatory molecules, like cytokines.  Some of these molecules, like IL-6, tell your liver to make more hepcidin.  If your body frequently sends out inflammatory signals, it can actually make it so that your cells are less able to release their iron.  It can also make your bone marrow less able to make red blood cells. 
When your body releases inflammatory cytokines, your body thinks it is fighting an infection.  These cytokines tell your body to make white blood cells, which your body thinks it needs to fight the infection.  White and red blood cells are made from the same stem cells in the bone marrow.  If the body is making more white cells, it is inherently making less red blood cells.  In this way, chronic inflammation increases the level of hepcidin, so the body keeps iron in its stores and stops absorbing additional iron, while also stimulating white blood cell production and decreasing red blood cell production. 
There are other ways in which decreased iron affects red blood cells, including interfering with the release of erythropoietin from the kidney.  This is the molecule that tells your bone marrow to make red blood cells.  When iron is deficient, the survival of red blood cells is also shorter.
So regardless of dietary iron intake, many people with chronic inflammation are functionally anemic.