Contact sensitization to cosmetic series of allergens in female patients with rosacea: A prospective controlled study in China.

Abstract

Allergic contact dermatitis to cosmetics (ACDC) complicates the diagnosis and treatment of rosacea, and is increasingly observed in daily practice. The present study aimed to identify the contact allergens responsible for ACDC in Chinese female rosacea patients with or without suspected ACDC (SACDC). From a total of 1267 women with rosacea, 122 with SACDC, 145 without SACDC, and 100 age-matched healthy controls without rosacea or SACDC were examined on a voluntary basis. Skin patch tests with C-1000 cosmetic series (Chemotechnique Diagnostics, Malmo, Sweden) were conducted, including 20 selected allergens. Positive allergic reaction was found in 85.2% and 33.8% of SACDC and non-SACDC (P<.001), respectively, and 27.0% of healthy volunteers. Most reactions occurred at day 3, and the majority of all the examinees including normal controls reacted to more than 1 allergen. In SACDC patients, leading allergens were methylchloroisothiazolinone/methylisothiazolinone (28.7%), linalool hydroperoxide (27.1%), fragrance mix I (21.3%), methylisothiazolinone (17.2%), limonene hydroperoxides (16.4%), formaldehyde (14.8%), myroxylon pereirae (13.9%), and propolis (10.7%); the overall allergic reaction rate positively correlated with new onset of facial pruritus (P<.001). The occurrence of irritant contact reactions correlated with positive allergic reactions in rosacea patients with or without SACDC (P=.032 or P<.001, respectively). Preservatives and fragrances are primary culprits for ACDC in Chinese female rosacea patients. Patch testing should be considered in the suspected patients.