What should you know about red rash all over body?

A rash across many areas may follow a new medicine, viral illness, heat, a product used over a large surface, or an inflammatory condition. Drug rash can begin after starting or changing a medicine, while contact dermatitis may follow a shared exposure such as detergent or body product. Atopic dermatitis and psoriasis can affect broad areas and often bring itch, dryness, or scale. Scabies commonly causes marked itch and may affect household contacts; ringworm usually forms scaly, expanding patches. Note whether the rash blanches with pressure, has spots, welts, blisters, peeling, or bruising, and whether your mouth, eyes, or genital skin is involved. Do not assume the cause from redness alone.

Record when the rash began and list every recent medicine, supplement, food, product, illness, and travel exposure. Use gentle, fragrance-free skin care, keep cool, wear loose clothing, and avoid scratching. Do not start several new creams at once, as this can obscure the pattern. If a medicine seems linked, contact the prescriber promptly before changing an essential treatment. Avoid close skin contact and sharing towels until an infectious cause has been considered. Clear photographs taken in good light can show how the rash changes.

Seek emergency care for difficulty breathing, swelling of the face or tongue, faintness, confusion, rapidly worsening illness, widespread blisters, skin peeling, severe skin pain, or sores in the mouth or eyes. A widespread rash with fever, purple or bruise-like spots, or significant tenderness needs prompt assessment. Contact a clinician soon even without those signs if the rash follows a new medicine, is spreading, or is accompanied by joint pain or marked fatigue.

Could a medicine or recent exposure explain the distribution? What symptoms should make me seek urgent help? Do I need an examination, skin test, or treatment, and should household contacts take precautions?