We describe a 65-year-old patient with long-standing type 2 diabetes mellitus who presented with a 2-year history of papular lesions about 3-4 mm in diameter, hyperkeratotic, very itchy and located primarily on the back (fig. 1). Laboratory tests were unremarkable. A skin biopsy was taken. The hematoxylin-eosin stain showed an ulcerative lesion with collagen fibers, keratinous material and lymphocytic infiltration. The lower edge of the ulcer was interrupted by collagen fibers running perpendicular to it (fig. 2). These findings were consistent with APC. Use of topical corticosteroids and antihistamines did not result in any improvement of the skin lesions.
The lesions were treated for 2 months with topical tacalcitol (once daily) and disappeared completely (fig. 3). However, 4 weeks after finishing the treatment, the lesions recurred less severely, showing an early recovery after reintroduction of tacalcitol during 3 weeks. Now, the patient is treating himself when the lesions recur using the same treatment with full recovery between outbreaks.