An unusual presentation of a common disease.

We present a case of perforating granuloma annulare (PGA), in which we show the natural history of lesions and outline the different clinical types. Our patient responded well to intralesional triamcinolone acetonide 10mg/ml injections. Although she was otherwise well, PGA can be associated with diabetes mellitus in up to 17 percent of cases. Differential clinico-histopathological diagnosis, specifically in relation to necrobiosis lipoidica diabeticorum is being discussed. Treatment for PGA is difficult; apart from topical and/or intralesional steroids (clearance up to 54% in one case series), other options include Psoralen plus UVA (PUVA), systemic isotretinoin, chloroquine or hydroxylchloroquine, sulphapyridine, dapsone, topical application of imidazole creams, and liquid nitrogen. Spontaneous remission has also been reported in up to 77 percent in one case series.