A 57 year old man developed an erosion on the tip of his nose after cervical spine surgery. He was known to have porphyria cutanea tarda, a condition predisposing to skin fragility and exacerbated by ultraviolet light. The combination of trauma from the oxygen mask and ultraviolet from the lights in the operating theatre resulted in formation of a subepidermal blister and consequently an erosion. Complications such as this can be minimised by fitting filters over theatre lights and making medical and nursing staff aware of the potential for cutaneous injury after light trauma.

Bruce C Gee, specialist registrar, Andrew D Harris, specialist registrar, Sheelagh M Littlewood, consultant, Department of Dermatology, Queen's Medical Centre, Nottingham NG7 2UH