Study Finds Rise in Allergies to Cosmetic, Health Product Preservatives
By Larry Hand
NEW YORK (Reuters Health) - The prevalence of contact allergy to methylisothiazolinone (MI) and methylchloroisothiazolinone-methylisothiazolinone (MCI-MI) is increasing, according to a study from Ohio.
Dr. James S. Taylor from Cleveland Clinic and colleagues reviewed the medical records of consecutive patients presenting over a period of about two years with possible allergic contact dermatitis who later underwent patch testing.
Of 703 patients, 57 (8.1%) tested positive for contact allergy to MI and/or MCI-MI. Of those, 35 tested positive for MI only, five reactions were to MCI-MI, and 17 reactions were to both, the team reports in JAMA Dermatology, online November 4.
The prevalence of contact allergy to MI rose from six of 236 patients (2.5%) in 2012 to 16 of 235 patients (6.8%) in 2014.
The hands and face were the most commonly affected sites, and four patients had occupational contact dermatitis with allergies to MI or MCI-MI.
Soaps, cleansers, hair care products and cosmetics accounted for all the identified sources, the researchers say. Forty patients (70%) found MI or MCI-MI in personal health products, most often in wet wipes.
Of 23 patients with follow-up data, 17 (74%) improved with allergen avoidance.
The European Commission has banned MCI-MI from all leave-on body products, but still allows use at concentrations up to 15 ppm in rinse-off products, the researchers note. It allows concentrations of 3.8 ppm of MI in leave-on products and 15 ppm in rinse-off products
In the U.S., the Cosmetic Ingredient Review panel allows MCI-MI concentrations of 7.5 ppm in leave-on products and 15 ppm in rinse-off products For MI, maximum concentrations of 100 ppm are allowed for rinse-off products.
"The increasing prevalence of contact allergy to MI alone supports its addition to the standard series to identify cases missed by testing for MCI-MI only. . . . U.S. regulatory agencies must act to ensure patient safety," the authors concluded.
Clinicians should have "higher suspicion for allergy to MI and MCI-MI in patients with suspected contact dermatitis who are allergy-patch tested, especially for patients with putative allergy to wet wipes, sunscreens, other cosmetic products and paints," Dr. Taylor told Reuters Health by email.
Adding MI to an allergy patch testing series in addition to MCI/MI is necessary because "testing only the latter may miss MI allergy," he explained.
JAMA Dermatol 2015.