Symptom · Whole body
Rash
Also known as: skin rash, spots, hives
Any change in the colour or texture of the skin. Most rashes are harmless reactions, infections or inflammatory skin conditions; a few signal serious illness, especially when they come with fever, spread quickly or do not fade under pressure.
Seek urgent care if
- A rash that does not fade when a glass is pressed on it, especially with fever or drowsiness
- A rash with swelling of the face or tongue, wheeze or difficulty breathing
- Blistering, peeling skin, or a rash affecting the mouth, eyes or genitals after a new medicine
- A rapidly spreading hot, painful rash with fever
Common causes
Eczema (atopic dermatitis)Dry, itchy patches in the creases of elbows and knees.
Contact dermatitis and irritantsRed itchy skin where something touched it: nickel, detergents, plants.
Hives (urticaria)Itchy raised wheals that move around within hours, from allergy, infection or no clear cause.
Viral rashesChickenpox, measles, slapped cheek, hand-foot-and-mouth; often with fever.
Fungal infectionsRingworm, athlete's foot, thrush.
PsoriasisWell-defined red plaques with silvery scale on elbows, knees and scalp.
Acne, heat rash, insect bites
Less common causes
Meningococcal sepsisPurple spots or bruises that do not fade under a glass, with fever and being very unwell.
Drug reactionsWidespread rash days after starting a medicine; blistering or peeling is an emergency.
ShinglesA painful band of blisters on one side of the body.
CellulitisSpreading, hot, tender redness.
Autoimmune diseaseButterfly rash of lupus, the rash of dermatomyositis.
Skin cancerA changing mole or a sore that will not heal.
Often occurs with
Conditions to read about
How it is investigated
Educational content. This page explains what a symptom can mean so that the anatomy and the medical reasoning make sense. It cannot tell you what is causing yours: only a clinician who can examine you and order tests can do that.