The lesions in this condition are small, clear, thin-roofed vesicles that develop when the sweat duct is obstructed within the stratum corneum. They occur after sunburn or in response to excessive sweating in high environmental heat and humidity. Fever may also be a cause. The scalp, face, trunk, and intertriginous areas are sites of lesions. Itching is not a symptom. The vesicles resolve rapidly with the elimination of the causative environmental factor.