Sweet's syndrome triggered by ultraviolet light

Sweet's syndrome is a neutrophilic dermatosis associated with many different underlying conditions but only rarely is it triggered by environmental factors such as ultraviolet (UV) exposure. We present two cases of photoinduced Sweet syndrome. Our first patient, who was taking hydrochlorothiazide, presented photodistributed lesions, pathological phototest and neutrophilic dermatosis histopathology. The phototest normalized after drug withdrawal, suggesting that both UV light and hydrochlorothiazide were necessary to cause the lesions. Our second case presented lesions clearly induced by UV light and histologically consistent with Sweet's syndrome. The MED was decreased and the lesions were reproduced with nbUVB, suggesting the diagnosis of photoinduced Sweet's syndrome. In conclusion, we report a case of neutrophilic dermatosis induced by hydrochlorothiazide and UV light and a case of photoinduced Sweet's syndrome with reproduction of the lesions after nbUVB. Both patients had a pathologic photobiological study. Our report emphasizes the need to perform phototests in patients with photodistributed Sweet's syndrome.