‘You’re allergic to _what?’_ Five odd allergies to everyday things

Over 50 million Americans experience allergies each year. The most common allergens are tree, grass, and weed pollen; mold spores; cockroaches; dust mites; and cat, dog, and rodent dander. Some allergies, however, are more unusual. Let’s look at five strange allergies to everyday things.

Sun allergy

Solar urticaria is a chronic, acquired photosensitivity disorder that manifests as recurrent episodes of urticarial rash on areas of the skin exposed to the sun. This condition can be disabling and interferes with activities of daily living and quality of life. The condition usually begins in adulthood (median age: 35 years), although it can start at any age.

The underlying cause of solar urticaria is still undetermined, but it could be IgE-mediated because the onset of symptoms immediately follows exposure to sunlight. Alternatively, radiation from sunlight could activate a substance in the serum or dermis called chromophore, which can then lead to the degranulation of mast cells and allergic reaction. A diagnosis of this condition can be confirmed with photo testing. No definitive treatment exists for solar urticaria, but patients may respond to high levels of histamine H1-receptor antagonists. Phototherapy can be used to induce sensitization. Other possible treatments include intravenous immunoglobulins, plasma exchange, cyclosporine, afamelanotide, and omalizumab. But oral steroids don’t help with this condition.

Water allergy

People need water to live, which is why water allergy seems so weird. But there’s a rare condition called aquagenic urticaria where a person develops hives shortly after skin contact with water at any temperature. The inheritance pattern of this disease is unknown, and it mostly affects women. This condition, which is diagnosed in only 1 in 23 million people, generally manifests as hives, wheals, and itching after exposure to water. These symptoms abate about an hour after the water exposure is stopped.

Experts hypothesize that this allergy results from either an allergen found in water or an interaction between water and a substance on the skin, which then becomes toxic. In other words, experts don’t think that water is itself an allergen but rather a carrier for the allergen. Diagnosis of aquagenic urticaria involves a water-challenge test.

No evidence-based treatments exist for this condition, but antihistamines, omalizumab, phototherapy, and petroleum-based creams have been used. People with this condition must keep showers to under a minute and drink carbonated or distilled water.

Sperm allergy

Human seminal plasma hypersensitivity, or sperm allergy, is a rare reaction to semen that usually affects women. Symptoms can include hives, swelling, trouble breathing, or even anaphylaxis, and tend to manifest 10-30 minutes after contact with semen. This allergy can present after a woman first has unprotected sex or at any point during a woman’s lifetime—even after being with a long-term sexual partner. In women who have localized reactions to semen, the allergy is often misdiagnosed as vaginitis or a sexually-transmitted infection. The difference, however, is that women with sperm allergy don’t manifest symptoms after engaging in sexual activity using a condom.

Sperm allergy can make intimacy and conception a challenge, and thus can strain a relationship. It can be diagnosed by injecting a small amount of partner semen into the dermis. Desensitization, including the use of allergy shots, can help treat this condition. Alternatively, a couple intent on having a baby can employ artificial insemination or in vitro fertilization, where the sperm is washed. Of note, sperm allergy does not affect female fertility.

Clothing allergy

Textile fabrics can be natural, synthetic, or a blend of the two. Natural fibers include silk, wool, and cotton, whereas synthetic fibers include polyester, rayon, nylon, fiberglass, and spandex. Formaldehyde finishing resins, dyes, chemical additives, tanning agents, and glues can lead to allergic skin reactions. Formaldehyde resins are added to fabrics to make them wrinkle resistant. Other fabric additives that can result in allergic contact dermatitis include flame retardants and para-phenylenediamine, which is a chemical used in dyes. On a related note, metallic fasteners and studs can also cause allergic contact dermatitis upon skin exposure.

Women are most often affected by textile contact dermatitis, probably because they wear more form-fitting and colorful clothing. People who are obese, work in humid environments, work with textiles, or have atopic dermatitis are also at higher risk. Symptoms of this condition include redness, scaling, and itchiness that can manifest within hours or days of contact with the offending fabric. The areas most likely to be symptomatic are those most in contact with clothing, such as crooks of the arms, buttocks, and armpits.

Textile contact dermatitis can be diagnosed using a patch test. Avoidance of offending fabrics is recommended in patients with this condition, and patients should consider wearing untreated, loose-fitting linen or cotton clothes. Topical steroids can be used to treat symptoms, with antibiotics used to treat severe cases involving infection.

Pollen-food syndrome

This oral allergy syndrome entails a type I hypersensitivity reaction mediated by IgE antibodies. It’s an allergic reaction to fresh fruits, vegetables, or nuts in people allergic to pollen. Some fresh fruits, fresh vegetables, and nuts harbor similar proteins to those found in pollen. When antibodies to pollen cross-react with these ingested foods, the result is symptoms such as itchiness or swelling, mostly in the mouth and throat. Anaphylaxis can ensue, but because these pollen-like allergens are deactivated by gastric enzymes, this dreaded adverse effect is rare.

Of note, fruits and nuts closely associated with the birch tree—such as stone fruits, prunes, carrots, celery, almonds, hazelnuts, and peanuts—are the most common causes of pollen-food syndrome. People with this allergy should, therefore, avoid foods that cause it. The cooked form of these fruits and vegetables, however, are usually tolerable because heat deactivates the food allergens. Offending nuts should be avoided altogether.

Plus, one more ‘allergy’: Electrohypersensitivity

Exposure to electromagnetic fields has exploded with the advent of technology. Along with improvements to our daily lives, some worry that this exposure could result in unintended health consequences. Common sources of electromagnetic fields include computer monitors, mobile phones, tablets, and televisions. A small minority of people complain of a wide range of unspecified symptoms when exposed to electromagnetic fields, which is referred to as electrohypersensitivity by the WHO and others. Some of these people exhibit disability that makes activities of daily living nearly impossible and requires them to restructure their lives, quit work, stop going outside, and so forth. Interestingly, electrohypersensitivity is legally protected in Sweden because per Swedish law, the environment is viewed as the culprit. Suffice to say, most experts don’t believe that electrohypersensitivity is a physiologic allergy.