A polymorphic light eruption (PMLE) occurs in response to sunlight after a period of time in which the skin has been covered and scarcely exposed to the sun. It is caused by ultraviolet A (UVA) light or visible light.1 As such it may occur after sun exposure through a window, and rarely it can occur with exposure to fluorescent lighting. The term polymorphous indicates the variable nature of the rash but, for any individual, the rash tends to be fairly constant. It is described as idiopathic primary photodermatosis.
This is a companion discussion topic for the original article at https://patient.info/doctor/polymorphic-light-eruption-pro