4 Hidden Allergy Triggers

Still, food recalls due to undeclared sulfites do happen. And sulfites are also present in some medications, such as certain eye drops, injectable corticosteroids and some medications that contain gelatin.

If you know that you have an allergy, it’s important to be prepared. “Exposing oneself to food that [you] are allergic to — for instance, not reading labels,” can be risky, Namazy says. So can forgetting your EpiPen.

2. Natural products

Some ingredients in so-called natural products can “cause allergies such as contact dermatitis,” Ogden says. Allergic contact dermatitis is an itchy, red skin rash that is caused by direct contact with an allergen. It can erupt on the skin within hours of exposure (or sooner) and last for weeks. On brown and Black skin, the rash can appear leathery and hyperpigmented; on white skin, the rash is typically scaly and cracked. Blisters may form, and the skin may burn and feel tender.

Beware of the botanical milk thistle, “which is related to fall ragweed and can cause a reaction if you are allergic to ragweed,” Ogden says. And many product ingredients list “fragrance,” which can cause itchy rash-type symptoms. “Fragrance is one of the top triggers of contact dermatitis,” Ogden says.

Some people don’t find out that they’re allergic to a certain product until they go out in the sunshine and the two react — this is known as photoallergic contact dermatitis. Namazy says typical symptoms of photoallergic contact dermatitis include itching, blisters, red skin and swelling.

Other common causes of allergic contact dermatitis are not-so-natural products like adhesives for false eyelashes and toupees, nail polishes, hair dyes, perfumes and, of course, latex.

3. A familiar food

Allergies can emerge at any age, even after years of exposure and even if you’ve never had an issue with a particular food or medication.

“Many adults may not realize that foods they have eaten for years or even medications they have taken can cause allergy,” Ogden says. In fact, a survey of more than 40,000 people found that nearly half of adults with a food allergy developed it in adulthood. The research was published in 2019 in the journal JAMA Network Open.

Fish and shellfish are among the more common foods that can spark an allergy in adults, Ogden says. Another common adult-onset sensitivity is lactose intolerance (or malabsorption). This is different from a true dairy allergy, which is an immune system disorder, but nevertheless ushers in uncomfortable gastrointestinal symptoms for sufferers.

4. Houseplants

Houseplants can also contribute to your allergy woes. One reason is mold, which can grow in the soil and irritate people who have a mold allergy, Namazy says. (Sometimes avoiding overwatering will do the trick to keep mold at bay.)

Another reason is dust, which can collect on the leaves. And some plants are themselves allergenic, producing symptoms via indoor air or when they are touched.

When to see a doctor

Don’t let your allergy symptoms go untreated. Talk to your doctor if over-the-counter remedies are not controlling your symptoms, Namazy says, or if your symptoms persist beyond a few days. 

“Do not wait for weeks to go by,” Ogden says. Untreated or undertreated allergies “can lead to severe consequences, like bronchitis with intractable cough, asthma exacerbation with shortness of breath, cough and breathing issues, sinusitis, and conjunctivitis,” an eye infection.

Finally, consider getting tested for allergies. Knowing what’s causing your allergies can help you avoid your triggers.