NEW ORLEANS – Suspect an allergic reaction to inactive ingredients in topical corticosteroids when patients do not improve despite usual treatment regimens, a retrospective study suggests.
"An allergy prevalence of 4% for an emulsifier widely used in corticosteroids and personal care products is very important," Brienne Danielle Cressey said at this year’s annual meeting of the American Contact Dermatitis Society.
Brienne Danielle Cressey
Ms. Cressey and her associates in the dermatology department at Tufts Medical Center, Boston, reviewed charts of 591 patients who were patch-tested between November 2008 and May 2010. They found that 24 of these patients (4.1%) had positive reactions to a sorbitan emulsifier found in many corticosteroid formulations.
Specifically, 3.9% reacted positively to sorbitan sesquioleate (SSO); 0.85% to sorbitan monooleate (SMO); and 0.7% to both.
"It was thought previously to be an uncommon allergen," said Ms. Cressey, a student at the Maine Medical Center Tufts University School of Medicine (class of 2013) in Portland. In a previous study conducted at Tufts University, researchers found an 8.9% prevalence of sorbitan allergy among 112 dermatitis patients (Dermatitis 2008;19:323-7).
Even though sorbitan allergy was less common in the current study, "we feel it’s still an important allergen, with a prevalence greater than 1%." These emulsifiers are not included in the standard patch-testing series, Ms. Cressey said.
Patients were patch-tested using the Tufts Medical Center standard series and a preservative series containing SSO in 20% petrolatum and SMO 5% in petrolatum. Results were read at 48 and 72 hours. The majority were weak reactors: 22 patients were + and 2 were ++. "Our only two patients with 2+ reactions were children with generalized dermatitis," Ms. Cressey said.
Only one patient reacted to any of the four different corticosteroid screening chemicals tested, confirming that these reactions were caused by the sorbitan emulsifiers.
In the positive reaction group, the average duration of contact dermatitis was 43 months, the mean age was 40 years, and 46% were atopic. Dermatitis of the upper extremity and face was the most common.
The sources of sorbitan exposure were personal care products (10 patients), topical corticosteroids (9 patients), and ingestion (5 patients). Ingestion included, for example, sorbitans as a medication ingredient, Ms. Cressey said. "One patient with axillary dermatitis was using deodorant with sorbitol," she added.
The fact that the majority of reactions to SSO were weak raises a question as to whether this emulsifier is a contact or irritant allergen, Ms. Cressey said. Because 27 of 591 patients also were questionable for SSO reactions, "SSO is most likely not an irritant," she said.
In addition to topical corticosteroids, sorbitol-based emulsifiers are found in topical antibiotics, topical antifungals, topical retinoids, and moisturizing creams and lotions (Dermatitis 2008;19:339-41). This publication includes a list of products that commonly contain SSO, sorbitol, and sorbitol derivatives.
Ms. Cressey said that she had no relevant disclosures.