Allergic contact dermatitis caused by calcipotriol.

Background: Calcipotriol, a synthetic vitamin D analogue, is widely used for the topical treatment of psoriasis. It often causes irritant reactions, whereas allergic contact dermatitis has less commonly been reported.

Objectives: To report on 6 patients (among them an 11-year-old child) who presented with eczematous lesions complicating pre-existing dermatitis, observed in our tertiary referral patch test clinic between 2004 and 2016.

Methods: Patch tests were performed with the commercial preparation used by the patients and/or its ingredients, including calcipotriol (2 or 10 µg/ml in isopropyl alcohol), according to ESCD patch test guidelines.

Results: Allergic contact dermatitis was confirmed in all cases, and the lesions improved following treatment with topical corticosteroids and/or oral medication.

Conclusions: When topical treatment with calcipotriol fails to improve, or even worsens, existing skin lesions, contact allergy should be suspected. A patch test concentration of 2 µg/ml in isopropyl alcohol seems to be the most suitable. According to the literature, patients sensitized to calcipotriol may tolerate topical therapy with other vitamin D3 analogues, particularly tacalcitol.