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

BACKGROUND

Allergic contact dermatitis to cosmetics (ACDC) complicates the diagnosis and treatment of rosacea, and is increasingly observed in daily practice.

AIMS: The present study aimed to identify the contact allergens responsible for ACDC in Chinese female rosacea patients with or without suspected ACDC (SACDC).

METHODS

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.

RESULTS

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).

CONCLUSIONS

Preservatives and fragrances are primary culprits for ACDC in Chinese female rosacea patients. Patch testing should be considered in the suspected patients.