Around 50 million Americans suffer from some type of allergy, including indoor/outdoor, food, drug, latex, insect, or skin and eye allergies. Among all ages, allergy is considered the fifth leading chronic disease in the United States. A presentation at the American College of Allergy, Asthma, and Immunology (ACAAI) Annual Scientific Meeting has found that allergy medications used to relieve mild and severe symptoms can sometimes result in more severe allergic responses.

"Allergy to a topical corticosteroid may not be evident right away because its job is to bring down inflammation," allergist Luz Fonacier, ACAAI fellow and presenter, said in a statement. "But you should suspect an allergy to your medication if your rash doesn't respond, gets worse with the medication, or improves initially, then flares."

Fonacier and her colleagues outlined possible reactions to topical skin preparations, certain patients who may be hypersensitive to antihistamines, and various drugs used to treat asthma that may also result in an allergic reaction. Allergy sufferers who experience an allergic response, such as worsening of itching or rash, should discontinue medication use and schedule an appointment with their allergist. A patch test can be used to determine if a reaction is being caused by the preservatives, fragrance, or delivery system of topical medications.

"It's surprising that the main medications used to relieve allergies can cause new allergies, or worsen already existing allergies," said allergist Dr. Sami Bahna, ACAAI past president and presenter. "They are, therefore, rarely suspected. The majority of antihistamine reactions affect the skin, appearing as hives or a rash."

According to ACAAI recommendations, between five and 10 percent of allergic reactions are caused by common medications that are not used for allergy or asthma relief. Certain medications come with a higher risk of causing an adverse reaction. They include antibiotics (penicillin), non-steroidal anti-inflammatory medication (ibuprofen), and anticonvulsants. Reactions to oral medications are less likely to occur compared to those rubbed on the skin or given via injection.

Source: Fonacier L, et al. Allergy sufferers are allergic to treatment more often than you'd think. American College of Allergy, Asthma and Immunology (ACAAI) Annual Scientific Meeting. 2014.