Allergic contact dermatitis caused by fragrances and formaldehyde is common, 1,2 but pustular dermatitis as a manifestation of contact allergy is rare. 3 We report a case of therapy-resistant rosacea for which (occupational) contact allergy to fragrances, and to a lesser extent formaldehyde, was identified as an aggravating factor.
CASE REPORTA 50-year-old non-atopic female hairdresser began to suffer from erythematous and pustular dermatitis on the cheeks, forehead, and chin ( Figure 1). Having been diagnosed with papulopustular rosacea, she had been treated with topical metronidazole and ivermectin, and with systemic tetracyclines, without any relief. The patient herself had related episodic flare-ups of the dermatitis to her own cosmetics, but also to airborne exposure to cosmetics used at the hair salon. Therefore, she had strongly restricted her own use of these, and had been off work for 6 months, leading to significant amelioration, but not complete resolution. Besides a relapse of dermatitis, she mentioned the occurrence of migraine-like headache and general discomfort whenever she re-entered the hair salon, or whenever she came into contact with heavily scented customers.Because of these potential (and partially occupational) environmental factors contributing to her skin condition, she was referred to our department. No hand dermatitis was present, and nor had it been present in the past during any working activities, during which she regularly wore (nitrile) gloves. The facial dermatitis indeed suggested a diagnosis of papulopustular rosacea. However, atypical features, such as vesiculation, eczematization and itching, indicated that contact allergy might also be present. Therefore, patch tests were performed with the Belgian baseline series (based on the recently revised European baseline series), 4 and with cosmetic, fragrance, metals and hairdressing series, all from Chemotechnique Diagnostics (Vellinge, Sweden). All preparations were applied on Allergeaze patch test chambers (SmartPractice, Calgary, Canada), and occluded for 2 days with Fixomull stretch (BSN Medical, Hamburg, Germany). Readings were performed on day (D) 2 and D4 according to European Society of Contact Dermatitis guidelines. 5 On D4, formaldehyde 2% aq. gave a positive reaction (++), as did the weak releaser imidazolidinyl urea (?+) and the stronger releaser diazolidinyl urea (+). Moreover, positive reactions were observed to fragrances: fragrance mix II (+), Myroxylon pereirae resin (+), and, especially, limonene hydroperoxides 0.3% and 0.2% pet. (++) ( Figure S1), but not to linalool hydroperoxides 1% and 0.5% pet. Interestingly, during patch testing, the patient experienced a pronounced flare-up of pustular skin lesions on her cheeks and forehead ( Figure S2).As the patient had already discarded the majority of her formerly used cosmetic products, we could not verify any particular relevance related to the use of these personal care products, with the exception that most of them were scented. We asked her to verify her occupatio...