rash

In medicine, eruption on the surface of the skin. It is usually raised and red or it may contain vesicles filled with fluid. It may also be scaly or crusty. Characteristic rashes are produced by infectious diseases, such as chickenpox, measles, German measles, and scarlet fever. The severity of the rash usually reflects the severity of the disease. Rashes are also produced as an allergic response to stings from insects and plants. These are often alleviated by antihistamines and they usually resolve within a few days.

Chronic rashes are present in patients with some skin diseases, such as eczema and psoriasis.