What should you know about dermatitis rash?

A rash is a visible skin change rather than a diagnosis. Atopic dermatitis often brings itch and dry sensitive skin; contact dermatitis follows exposure to an irritant or allergen. Heat rash appears where sweat and friction are trapped, while intertrigo affects skin folds. Psoriasis can produce sharply defined scaly plaques. Ringworm may form a scaly advancing edge, and scabies often causes intense night itch with a household pattern. A drug rash can begin after a new medicine.

Note when the rash began, where it started, how it has changed and what touched the area beforehand. Use lukewarm water, a bland fragrance-free moisturiser and loose breathable clothing. Avoid scratching, new cosmetics and unprescribed combination creams until the cause is clearer. Do not stop a prescribed medicine without speaking with the prescriber, even if you suspect a drug eruption.

Seek emergency help for trouble breathing, facial or tongue swelling, faintness, blistering, skin peeling, painful widespread redness, or sores in the mouth or eyes. Arrange prompt medical review for fever, pus, rapidly spreading warmth, a rash after a new medicine, or a rash in an infant. A persistent, recurrent or unexplained eruption also merits assessment because treatment for fungal infection, scabies, eczema and psoriasis differs.

Ask what features support the diagnosis, whether you need a skin scraping, allergy assessment or medicine review, and which products or activities should be avoided. Share photographs showing how the rash looked at its earliest stage.