INTROUCTION
Pyoderma gangrenosum (PG) is a rare non-infectious neutrophilic dermatosis of unknown etiology, characterized clinically by chronic and recurrent cutaneous ulcers with a necrolytic border and is commonly associated with underlying systemic disease. About 33-50% of the patients are known to have various underlying diseases such as inflammatory bowel disease (IBD), hematological malignancies and rheumatoid arthritis.1,2 Whereas palmoplantar pustulosis (PPP) presents with erythematous and scaly plaques studded with sterile pustules localized on the palms and/or soles and has a chronic and relapsing course. It is commonly associated with psoriasis vulgaris and or psoriatic arthritis.3
Although the pathogenesis of PG and PPP is poorly understood, recent studies have suggested that dysregulation of the innate immunity involving several common cytokines such as tumor necrosis factor-a (TNF-α), interleukin (IL)-17 and (IL)-23 may play important role in the development of both PG and PPP and share a common characteristic histological feature of neutrophilic infiltration in skin.4,5,6 Psoriasis and psoriatic arthritis have been found to be associated in up to 10% of PG patients7but the coexistence of PG and PPP in the same patient has been reported only in 5 cases in the literature till date8,9,10 and all were reported from Japan. We report herein a female patient with PPP who developed PG on her lower leg as a first case report other than in Japanese population and tried to justify the coexistence of both the conditions based on the review of the literature.