What should you know about a red scaly rash?

Dry, itchy patches can occur with atopic dermatitis, while a rash limited to an area touched by a product may fit contact dermatitis. Psoriasis often forms thicker, defined scale and may recur. Heat rash favours hot, sweaty, covered skin. Ringworm may form an enlarging ring with a clearer centre; scabies can cause intense itch, often worse at night, with small bumps in characteristic sites. Intertrigo affects skin folds where moisture and friction collect. A drug rash may begin after a new medicine. The same colour and scale can have different causes.

Wash gently, pat dry, and apply a fragrance-free moisturiser. Keep folds cool and dry, wear loose breathable clothing, and pause new soaps, creams, detergents, or cosmetics. Avoid scratching and do not share towels or clothing if an infection or infestation is possible. Photograph the rash and record its onset, spread, itch, pain, fever, exposures, and medicines. A clinician can choose treatment after examining its shape and distribution.

Seek urgent care for breathing difficulty, facial swelling, blistering, skin peeling, purple spots, severe pain, fever with a rapidly spreading warm rash, or involvement of the eyes or mouth. Arrange a prompt appointment for pus, increasing tenderness, a rash after starting a medicine, or a rash that persists, returns, or spreads despite removing an irritant. Children, older adults, and people with weakened immunity may need earlier advice.

Which features distinguish eczema, contact dermatitis, heat rash, psoriasis, ringworm, scabies, intertrigo, and a drug rash? Should I stop or change any medicine, and who should guide that decision? Do I need a scraping, swab, or review if the rash changes?