Rash all over the body: what to know

A rash may appear as flat colour change, raised spots, blisters, scaling, or wheals that move from place to place. New soap, detergent, cosmetics, plants, heat, or medicines can irritate or inflame skin. It may also accompany a viral illness or conditions such as [Atopic Dermatitis](/conditions/atopic-dermatitis/), [Contact Dermatitis](/conditions/contact-dermatitis/), [Drug Rash](/conditions/drug-eruption/), or [Scabies](/conditions/scabies/). The pattern, itch, pain, fever, and whether other people are affected help a clinician narrow the possibilities. A rash does not identify one diagnosis by itself.

Record when the rash began and take clear photographs in good light. List new medicines, foods, products, travel, illness, and possible contact with someone itchy. Use lukewarm water, a fragrance-free moisturiser, loose clothing, and gentle cleansing. Avoid scratching, heat, and starting several new creams at once because these can obscure the pattern or irritate skin. Do not stop a prescribed medicine without speaking with the prescriber, unless emergency clinicians tell you to do so. Avoid close skin contact and shared towels if an infectious cause is possible.

Get emergency help for breathing difficulty, swelling of the face or tongue, faintness, confusion, or rapidly spreading hives. Seek urgent assessment for purple or bruise-like spots, blistering, skin peeling, severe pain, high fever, stiff neck, or involvement of the eyes or mouth. Arrange a clinical review when the rash is widespread, persistent, recurring, or interfering with sleep, even if you otherwise feel well.

What features of this rash help distinguish irritation, allergy, infection, or inflammation? Could a recent medicine or product be contributing? Do I need tests, treatment, or precautions around household contacts? Which changes should prompt same-day care?