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

Evaluation of Delayed Contact Hypersensitivity in Patients with Rosacea

Introduction

Rosacea is a common chronic inflammatory dermatosis characterized by erythema, telangiectasia, papules, and pustules on the central face. The frequency of contact sensitization complicating rosacea and its therapy is unknown, with only few studies published in the literature. In the present study, we aimed to evaluate contact sensitivity in patients with rosacea.

Methods

A total of 50 rosacea patients and 50 age- and sex-matched healthy controls were enrolled. Both groups were patch tested with the European Baseline Series.

Results

A positive reaction to at least one allergen of the European Baseline Series was observed in 15 (30%) of rosacea patients and 10 (20%) of the healthy controls. Although the rate of positive reaction in the rosacea group was higher than in the controls, no statistically significant difference was documented. In addition, the total number of positive reactions to allergens in the rosacea group was higher than the control group, namely, 26 versus 17.

Conclusion

Contact hypersensitivity may coexist with rosacea. Its identification holds significant clinical relevance, influencing the long-term management and justifying the application of patch testing in rosacea patients.

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.