raised, flat-topped skin areas over 1 centimeter wide
Plaques, in the context of dermatology and hair, refer to raised, flat-topped areas on the skin that are larger than 1 centimeter in diameter. They can be a symptom of various conditions, such as psoriasis, where they appear as red, scaly patches. In the context of alopecia, plaques might indicate an underlying inflammatory process affecting the hair follicles.