It sounds impossible, but some people experience severe immune reactions to others – a complex phenomenon scientists are just beginning to understand.
Imagine contact with another person causing burning, swelling, or even difficulty breathing. This challenging reality is faced by individuals like Maura, a 43-year-old in Ohio. In her twenties, she began experiencing painful burning and swelling in her genitals after unprotected sex. This initially went unaddressed due to discomfort, worsening over time despite changing hygiene products. It only occurred after contact with semen.
The issue escalated dramatically with a new partner who used condoms regularly. One night, after sex where a condom was suspected of leaking, Maura’s tongue swelled rapidly, triggering a severe reaction she describes as near asphyxiation. Luckily, her partner had an inhaler, which she was able to use just in time. This terrifying experience led to a diagnosis of seminal plasma hypersensitivity, commonly known as semen allergy. Maura, who has a history of asthma and other allergies, believes condoms have been life-saving for her, leading her and her long-term partner to be extremely cautious. Her story highlights the severity and unexpected nature of these reactions, something she hadn’t known was possible.
While extremely rare, documented cases show some people have severe immune responses to components of other human bodies. These often-misunderstood conditions don’t just impact health; they can profoundly affect relationships, work, and daily life. But how do these reactions happen? Are they “true” allergies, or something else entirely? The emerging science surrounding these strange responses is offering fascinating glimpses into human body chemistry and the quirks of the immune system.
When the Immune System Reacts to Others
Immune reactions to other people can stem from various sources:
External Substances: Often, sensitivities are triggered by products others use. Skin can carry synthetic fragrances from deodorants or aftershaves, with over 150 fragrances known to cause contact allergies. Allergens can also be transmitted via bodily fluids during intimate contact. For instance, individuals with severe food allergies have experienced reactions after kissing or having sex with someone who recently ate the offending food, even after hygiene measures. Nuts are the most commonly reported culprits during kissing, but saliva can carry residues from fruits, vegetables, seafood, or milk. Similarly, people with antibiotic allergies have reacted after sexual contact with partners who took those medications.
Suspected Reactions to Natural Body Emissions: While less understood, some reactions appear linked to natural body odours or chemicals emitted from skin. One woman with severe mast cell activation syndrome reportedly developed debilitating allergic reactions to her husband’s scent. Some doctors treating patients with mast cell disorders suspect sensitivity to others’ natural body emissions, although this link isn’t definitively proven. Human skin constantly releases gases contributing to body odour, including chemicals like toluene.
People Allergic To Me (PATM): This mysterious and isolating phenomenon involves individuals whose presence causes others to develop allergy-like symptoms (coughing, choking) in their vicinity. Recent Japanese research investigated skin gases from people reporting PATM symptoms and found significantly higher levels of toluene (39 times more on average) compared to a control group. Researchers suggest that PATM patients may have a reduced ability to break down toluene, leading to its buildup and release through the skin. However, PATM is not yet a widely recognized medical condition with established diagnostic criteria.
Allergies to Bodily Fluids
Beyond external substances or body gases, immune reactions can be triggered by proteins within certain bodily fluids.
Semen Allergy (Seminal Plasma Hypersensitivity): This is perhaps the most recognized, though still poorly understood, fluid-borne sensitivity. Symptoms range from localized hives and intense pain (“like acid” or “a thousand needles”) at the contact site to potentially life-threatening anaphylaxis. While most reported in women aged 20-30, only fewer than 100 cases have been formally documented, though experts estimate tens of thousands may be affected in the US alone. The primary allergen is typically a prostate-specific antigen protein found in seminal plasma (the fluid part of semen, not the sperm). Diagnosis usually involves a skin prick test using a partner’s fresh sample. Lack of animal models and few affected individuals make large-scale research difficult. Many patients are unfortunately misdiagnosed or inadequately treated due to limited medical awareness. Treatment approaches exist, including a desensitisation procedure developed by some experts where diluted seminal fluid is gradually introduced vaginally to build tolerance to a specific partner’s semen. Notably, data on semen allergies among men who have sex with men is significantly lacking.
Potential Cervicovaginal Fluid Allergy: While almost no published research exists, some anecdotal reports suggest sensitivity to cervicovaginal fluid. One dermatologist in Poland treated a male patient whose genitals became red and itchy after vaginal intercourse and whose face itched after cunnilingus. Doctors had previously dismissed his idea of an allergy, but he responded well to antihistamines. A survey by the same researcher suggested this condition might be as common as semen allergy, with sufferers reporting redness, itch, burning, swelling, and hives. Unlike seminal plasma hypersensitivity, early findings suggest repeat exposure might* lead to desensitisation in some cases, potentially explaining why many young adults continue relationships despite discomfort. Condoms would not offer protection in this scenario. Further research is needed to confirm this potential condition.
These cases underscore the intricate ways our immune systems interact with the world around us, including other people. It’s a reminder that while we are attuned to common allergens like pollen or pet dander (which, incidentally, can also cause reactions in animals like polar bears allergic to human dander), the biological frontier of human-to-human sensitivities remains largely uncharted territory, profoundly impacting the lives of those affected.
Understanding these rare conditions is crucial not just for those who suffer from them, but for advancing our broader knowledge of immunology and potentially paving the way for better diagnosis and treatment in the future.
