The avenues by which a person can suffer symptoms as a result of sex are almost endless. I am asked often about the mechanism by which mast cell patients can react to foreplay or intercourse. The reason it has taken so long to put this series together is not because of a dearth of information, but because there is so much. The research on this topic is deep, if not always to the point: Why do some people react badly to having sex?
There are a number of reasons why sex can cause allergic symptoms, which explains why intimacy is often fraught with anxiety for mast cell patients. So let’s start with the entry level: kissing.
It is widely accepted that kissing can transfer allergens via saliva, or contact between skin or oral mucosa. Allergic reaction after kissing is not even especially unusual. 5-12% of IgE food allergic patients have had at least one reaction after kissing. Peanuts, walnuts, and tree nuts are the most common offenders. Rash around the mouth, hives around the mouth, flushing, angioedema of lips, mouth, tongue and throat, wheezing and hives all over the body have all been reported in this situation. Usually symptoms present within minutes, but there are literature references to reactions developing up to three hours later.
In a group of 26 volunteers that ate peanut butter, the protein reached its highest concentration in saliva five minutes after consumption. After an hour, the protein was undetectable. Several methods for clearing the protein were tested. Brushing teeth, rinsing mouth, or both, waiting an hour after consumption, and waiting an hour and then chewing gum, all reduced protein concentration by over 80%. However, waiting one hour after eating was still the most effective way to clear the protein from the mouth.
Though much less common than transfer of food allergens, it is possible to transmit medications via saliva. In literature, all reports of this phenomenon involve ingestion of β-lactam antibiotics, including penicillin derivatives. In these cases, the patients had symptoms of oral allergy syndrome with hives over large parts of the body.
The quality of the kissing is certainly a factor. How deep is it? How much hard? How much friction? How wet? Mast cell patients often react to physical stimuli like this. It’s not hard to imagine a situation where the pressure and heat of kissing cause local mast cell degranulation. I found a (non-scientific) article describing a woman with aquagenic urticaria who reacts to kissing because it’s wet. For patients allergic to sweat, that could also cause a kissing reaction.
I feel like I should throw out there that you can react to allergens returned to the mouth by vomit. Mostly because there isn’t really anywhere else to put it. So it’s here. The warning about vomit is in the kissing post. How did this get to be my life?
BUT GUESS WHAT GUYS?!?!?!? Kissing can also be good for allergy patients. One study reported that that kissing decreased wheal response (the formation of red swollen areas) was decreased 28-34% in patient allergic to dust mite and Japanese cedar pollen. This patient group had allergic rhinitis and atopic dermatitis. It didn’t decrease the response to injection of histamine, which means the benefit from kissing in this study is not directly blocking histamine. Plasma levels of neurotrophins were decreased in these patients. Neurotrophins have a complex relationship to mast cells, so it’s possible that neurotrophins block something that tells mast cells to release histamine.
I know everyone wants to know – how can I kiss safely? So hang in there, because it’s coming. Along with the answers to all of the “embarrassing” sex questions I have ever been asked.
Liccardi G, et al. Intimate behavior and allergy: a narrative review. Annals of Allergy, Asthma & Immunology 2007; 99: 394-400.
Maloney JM, et al. Peanut allergen exposure through saliva: assessment and interventions to reduce exposure. J Allergy Clin Immunol 2006; 118: 719-724.
Liccardi G, et al. Drug allergy transmitted by passionate kissing. Lancet 2002; 359: 1700.
Sonnex C. Genital allergy. Sex Transm Infect 2004; 80: 4-7.