December 2014: Post summaries and take home points

Food allergy series: Risk factors for developing food allergies

  • Genetics is a factor in development of food allergies.
  • Poor skin integrity makes food allergies more likely.
  • Children with peanut or tree nut allergies usually react on the first ingestion.
  • Household peanut exposure is a risk factor for peanut allergy in infants.
  • Not clear if maternal diet while gestating can affect food allergies.
  • Low vitamin A and low vitamin D are risk factors.
  • Sun exposure and vitamin D deficiency may be connected to food allergies.
  • Hygiene hypothesis posits that changes in hygiene and cleaning has caused immune changes that may lead to allergies.
  • Gut microbiota also important in food allergies.

Food allergy series: FPIES (Part 1)

  • FPIES is the most severe GI food hypersensitivity that is not IgE mediated.
  • Thought to be caused by a delayed allergic pathway.
  • Causes profuse, repetitive comiting, diarrhea, acute dehydration, lethargy and weight loss.
  • Vomiting usually occurs 1-3 hours after eating offending food.
  • Vomiting is seen in 100% of cases.
  • Diarrhea is seen in 24% of cases.
  • Can cause low blood pressure and hypothermia.
  • Chronic symptoms can develop if food is not avoided.
  • About 75% of patients look seriously ill.
  • 15% have blood pressure low enough to require hospitalization.
  • FPIES usually onsets between 1-3 months of age, but can be as late as 12 months.
  • Symptoms usually occur 1-4 weeks after introducing cow’s milk or soy.
  • About 30% later develop atopic conditions.
  • 20% have family history of food allergies.
  • 80% react to more than one food.
  • Usually improve after beginning casein hydrolysate based formula.

Food allergy series: FPIES (part 2)

  • FPIES is diagnosed clinically.
  • Endoscopy and biopsy is often performed to rule out other conditions.
  • GI tract of FPIES patients shows inflammatory changes, such as ulceration and bleeding.
  • Baseline intestinal absorption is usually normal.
  • Food specific IgE is not usually present.
  • FPIES is managed with diet.
  • Exclusive breastfeeding can be protective against FPIES.
  • Oral food challenges require significant precautions and medical supervision.
  • Challenges are recommended every 18-24 months in asymptomatic patients.
  • 60% of FPIES cases resolve by three years of age.
  • In the US, only 25% of cases resolve by three years of age.
  • Most FPIES patients have some form of atopic disease.
  • Some patients may change from an FPIES type reaction to an IgE allergy type reaction.
  • Prevalence is different in different populations.
  • Median age for resolution of FPIES depends on the food and ranges from 4-7 years of age.
  • FPIES overwhelmingly affects very young children.
  • In very rare cases, older children and adults develop FPIES to fish or shellfish.

Food allergy series: Eosinophilic gastrointestinal disease (Part 1)

  • Eosinophilic gastrointestinal disease (EGID) is when eosinophils cause disease in the GI tract.
  • Eosinophils are white blood cells with similar functions to mast cells.
  • Eosinophils fight infections and participate in allergic response.
  • Eosinophils can degranulate.
  • Many GI conditions can elevate eosinophils in the GI tissue.
  • No consensus on what is a high eosinophil count/hpf.
  • Eosinophilic gastroenteritis can affect any part of the GI tract, but usually the stomach and small intestine.
  • Eosinophilic gastroenteritis causes swelling of the Gi tract, eosinophils in the tissue and ulcerations.
  • 50-70% of eosinophilic gastroenteritis is thought to be from allergic reactions.
  • The reason for eosinophilic gastroenteritis is not clear.
  • Eosinophilic esophagitis is 15 or more eosinophils/hpf in at least one field.
  • Eosinophilic esophagitis can be allergic or not.
  • Eosinophilic colitis is a rare condition with sudden onset colon inflammation with eosinophil infiltration that often spontaneously resolves.
  • Eosinophilic enteritis is limited to the small intestine.
  • Allergic proctocolitis affects rectum and/or colon of children under the age of 2.
  • Allergic proctocolitis can be the result of food allergy, most often soy or cow’s milk.

Food allergy series: Eosinophilic gastrointestinal disease (Part 2)

  • There are many conditions that can cause eosinophils to be increased in the GI tract.
  • Allergy associated colitis is when eosinophils aggregate in the small and large intestines as the result of an allergic reaction.
  • Hypereosinophilic syndrome is when people have too many eosinophils in the blood. Rarely, this causes eosinophils to become elevated in the colon.
  • Crohn’s disease causes inflammation of the digestive tract. Eosinophils in the GI tract can be elevated due to inflammation.
  • Ulcerative colitis causes inflammation of the colon. Eosinophils can be elevated in the colon due to inflammation.
  • Collagenous colitis causes inflammation of the colon and rectum. Eosinophils can be elevated. It may occur due to drug reactions.
  • Lymphocytic colitis causes inflammation of large portions of the colon. Eosinophils can be elevated in the mucosal layer.
  • Autoimmune colitis is when autoimmune patients experience colon inflammation. Eosinophils and mast cells are usually found together in affected tissue.
  • Graft versus host disease is a complication of a bone marrow transplant. Eosinophils can be elevated, including in the GI tract.
  • Peripheral/intestinal T cell lymphoma is a cancer that usually affects the small intestine. Eosinophils infiltrate the affected tissue.

Food allergy series: Eosinophilic gastrointestinal disease (Part 3)

  • 70% have family history of allergies
  • 10% have immediate family member with EGID
  • Can cause abdominal pain, GI dysmotility, vomiting, diarrhea, trouble swallowing, anemia, low blood protein and failure to thrive
  • Can cause malabsorption
  • EGID patients are very sensitive to foods. Eggs, milk and fish are most common problem foods.
  • Elimination diets are mainstays of treatment
  • Complete resolution often seen with elemental amino acid diet
  • Reintroduction of foods is not usually tolerated
  • Steroids effective but don’t produce lasting results
  • Mast cells often increased in EGID biopsies
  • Current treatment options not great

Food allergy series: Eosinophilic esophagitis (Part 1)

  • EoE patients are three times more likely to be male than female
  • Most patients have history of atopic disease
  • Usually presents in childhood or after third decade of life
  • Adults tend to have trouble swallowing, food impaction and upper abdominal pain
  • Children have less specific symptoms, including vomiting, abdominal and chest pain
  • 50-60% have at least one atopic condition
  • 15-43% have IgE mediated food allergies, are at greater risk for food induced anaphylaxis
  • No consensus on how many eosinophils/hpf is high

Food allergy series: Eosinophilic esophagitis (Part 2)

  • Endoscopy with biopsy is only reliable diagnostic method
  • May look normal by eye, so multiple biopsies should be taken
  • Mast cells are increased in EoE more than in GERD
  • Other tests rule like esophageal manometry, pH testing and barium swallows can help rule out other conditions
  • Important to exclude GERD
  • 40-50% EoE patients have increased in blood eosinophils
  • When EoE is effectively treated, blood eosinophil count decreases
  • Patients with EoE are found to have overexpression of several proteins
  • Other genetic links have been found

Food allergy series: Mast cell food reactions and the low histamine diet

  • Minimizes histamine in food consumed
  • Histamine from outside sources can induce mast cell degranulation
  • Common problem foods for mast cell patients, like alcohol, vinegar and aged cheeses, are high histamine and cause degranulation
  • There are many different versions of this diet. I use this one.
  • Avoid fermented foods, preservatives, dyes, leftovers, anything overly ripe, canned and pickled products
  • Recommends strict adherence for four weeks to determine if it works
  • Not all recipes labelled low histamine are low histamine

Food allergy series: Eosinophilic esophagitis (part 3)

  • Treatment first rules out GERD or PPI responsive esophageal eosinophilia by treatment with PPIs for 8-12 weeks
  • Some patients have primary EoE and secondary GERD
  • Dietary management is the cornerstone of EoE treatment
  • Dietary management is very effective in children, can achieve remission
  • Food tolerance is unlikely to be achieved even with long erm elimination
  • Steroids effective, but do not produce lasting benefits
  • Fluticasone and oral viscous budesonide effective in studies
  • Cromolyn has no clear benefit for EoE
  • Leukotriene receptor antagonists like Singulair might help, not clear
  • 11-55% of EoE patients suffer food impaction and require emergency intervention
  • Esophageal rings are common in EoE patients
  • Strictures larger than 1 cm in 11-31% of adults with EoE
  • Esophageal perforation can occur and may require surgery
  • Esophageal cancer and generalized EGID are not known to result from progression of EoE
  • Esophageal dilation is sometimes to treat difficulty swallowing and impaction

Food allergy series: Eosinophilic colitis

  • Can occur secondarily to many conditions, such as liver transplant and scleroderma
  • Less than 100 cases of primary eosinophilic colitis reported in literature
  • Experience lower GI symptoms, such as abdominal pain, constipation, diarrhea and rectal bleeding
  • More severe cases can cause malabsorption, obstructions, free fluid in the abdomen in weight loss
  • Symptoms often sudden onset, sudden resolve – relapsing/remitting
  • Dense eosinophilic infiltration in colon
  • Infiltration can occur in one large contiguous region or smaller isolated regions
  • No true consensus on what constitutes above average eosinophil count in GI tract
  • Sometimes have too many eosinophils in blood
  • Patients often have elevated total IgE
  • Treated with elimination diet, steroids, ketotifen and immunosuppressants