Paederus dermatitis is a skin irritation due to contact with certain rove beetle species, such as the Nairobi fly. It is also known as rove beetle rash, dermatitis linearis, spider lick, night burn, and Nairobi fly rash. We present a 40-year- old laborer with an erythematous plaque and blisters over his back, diagnosed as herpes zoster. He did not respond to conventional anti-herpetic treatment, and his lesions were spreading. There were no systemic symptoms. We revised our diagnosis to paederus dermatitis (PD). He was given topical antibiotics oral antihistaminics. He was symptomatically better, and his lesions slowly resolved after about three months.