A group or area of spots or an area of inflamed, red skin. A rash is often only temporary and is hardly ever a sign of a serious underlying health problem. A rash can be accompanied with fever or itching.
Rashes are classified according to whether they are generalised (covering the whole body) or localised (affecting only a certain part of the skin) and also by the type of spots present.
A macular rash consists of spots that are level with the surrounding skin discernible from it only by a difference in texture or colour. Popular and nodular rashes are made up of small, raised bumps, which can, or cannot be the same colour as the surrounding skin. A bullous rash has big blisters, a vesicular rash has little blisters, and a pustular rash has blisters that are pus-filled. A butterfly rash is a skin eruption across the cheeks with a narrow connecting band along the nose; it is characteristic of systemic lupus erythematous.
Rashes are the key sign of numerous infectious diseases, like chickenpox, and are a feature of many skin disorders, such a psoriasis and eczema. A rash can also show an underlying medical issue, such as the rashes seen in pellagra or scurvy, which are caused by vitamin deficiency. The rashes that are characteristic of urticarial (nettle rash) or contact dermatitis can be caused by an allergic reaction. Drug reactions, especially those to antibiotic drugs, are another widespread cause.
Diagnosis is based on the appearance and distribution of the rash, the presence of any other accompanying symptoms, and the likelihood of allergy.
Any underlying cause of the rash s treated where possible. An itching rash can be alleviated with a soothing lotion, such as calamine or an antihistamine drug.