What should you know about bumpy itchy rash?

Atopic dermatitis can cause itchy, dry, inflamed patches, while contact dermatitis may begin after exposure to a product, metal, plant, or fabric. Heat rash tends to affect warm, sweaty areas. Scabies often causes intense itching, sometimes worse at night, with bumps in characteristic areas and affected close contacts. Ringworm may form a scaly expanding edge. Psoriasis can produce well-defined, scaly plaques. A new medicine can also trigger a drug eruption, and moist skin folds may develop intertrigo.

Keep a short record of when the rash began, where it started, new products or medicines, travel, heat exposure, and anyone else who is itchy. Wash gently, moisturise dry skin with a bland product, and keep nails short. Avoid scratching, fragranced products, and sharing towels or clothing until an infectious cause is excluded. Do not stop a prescribed medicine without medical advice, but seek prompt guidance if the rash began after a new dose.

Get urgent help for breathing difficulty, swelling of the lips or tongue, faintness, blistering, skin peeling, or painful rash involving the eyes or mouth. Arrange a medical review for fever, pus, rapidly spreading redness, severe itch, suspected scabies or ringworm, or a rash that persists or repeatedly returns. A clinician may need to inspect the pattern and review medicines or contacts.

Could this be an allergy, infection, eczema, psoriasis, or infestation? Should household contacts be checked? Which products should I avoid? What warning signs mean I should seek urgent help?