What should you know about scarlet rash?

Colour alone cannot identify a diagnosis. Notice whether the skin is flat or raised, itchy or painful, dry or blistered, and whether it fades briefly when pressed. Location matters too: folds can become inflamed from moisture and friction, while a rash after a new product may fit contact dermatitis. Itchy scaling can occur with eczema, psoriasis, or ringworm; intense night-time itch may point toward scabies. A rash after starting a medicine deserves medical advice because drug eruptions can range from mild to serious.

A clinician may ask when the rash began, what touched the skin, which medicines or supplements you take, and whether anyone else has similar symptoms. Photographs showing its progression can help if the appearance changes before the appointment.

Use lukewarm water and a gentle, fragrance-free cleanser. Pat rather than rub, keep the area cool and dry, and apply a plain moisturiser if the skin is dry and unbroken. Avoid scratching, fragranced products, harsh exfoliants, and any recently introduced cosmetic until the cause is clearer. Do not share towels, clothing, or bedding when an infectious rash is possible. A pharmacist or clinician can advise whether a suitable treatment is appropriate after seeing the rash.

Seek urgent help for a rash with trouble breathing, swelling of the lips or tongue, faintness, rapidly spreading blistering, skin peeling, severe pain, or sores involving the eyes or mouth. Prompt assessment is also needed with fever, marked illness, purple or bruise-like spots that do not fade when pressed, or a rash soon after a new medicine. Arrange a routine review if it persists, recurs, becomes infected-looking, or interferes with sleep.

Could the shape and distribution fit an allergy, infection, or inflammatory condition? Should I stop any product or medicine? Do I need a swab, scraping, or other examination? What changes should make me seek urgent help?