Skin Rash: Causes, Diagnosis and Treatment

A rash may look like patches, spots, bumps, blisters, scales, cracks or raised welts. It can feel itchy, dry, sore, warm, burning or tender, although some rashes cause little sensation. Colour can range from pink or red to brown, purple or lighter than the surrounding skin, depending on your natural skin tone and the depth of inflammation. Note where it began, whether it is spreading, and whether anything new touched the skin or was taken before it appeared.

Seek urgent medical help if a rash comes with trouble breathing, swelling of the lips or tongue, faintness, fever with severe illness, rapidly spreading skin pain, purple or blistering areas, or involvement of the eyes or mouth. A rash that appears soon after a medicine also deserves prompt medical advice. For a mild, stable rash without these warning signs, arrange a routine assessment if it persists, recurs, disrupts sleep or develops signs of infection such as increasing warmth, pus or tenderness.

The causes below are listed alphabetically, not by likelihood. Atopic Dermatitis can produce itchy, dry, inflamed patches. Contact Dermatitis follows exposure to an irritant or allergen. Drug Rash may develop after a medicine. Heat Rash occurs when sweat and blocked ducts irritate the skin. Intertrigo affects skin folds where moisture and friction collect. Pityriasis Rosea can form a characteristic spreading pattern. Psoriasis often creates sharply outlined, scaly plaques. Ringworm is a fungal infection that may form an enlarging ring. Scabies causes intense itch and can affect household contacts. Tinea Versicolor changes pigment in areas where yeast overgrows. Hives are raised, shifting welts that can come and go.

A clinician examines the distribution, edges, surface and colour of the rash, then asks about onset, itch, pain, recent products, medicines, travel, contacts and existing skin conditions. They may inspect nails, scalp, mouth or other sites for related clues. Testing is sometimes used when infection, allergy or another condition needs confirmation; options can include a skin scraping, swab, patch testing or a small sample of skin. Bring a list of medicines and photographs showing how the rash changed.

Care may involve removing an irritant, protecting the skin barrier, reducing itch or treating an infection. A clinician may recommend moisturiser, an antifungal or another targeted medicine. Topical Corticosteroids can calm selected inflammatory rashes, but the strength, site and duration matter; use them only as directed, especially on the face, skin folds or broken skin. Do not share prescription creams or apply a leftover medicine to a new rash.

Use a gentle, fragrance-free cleanser and moisturiser, rinse sweat from the skin, and change damp clothing. Introduce new cosmetics or detergents one at a time so a reaction is easier to recognise. Avoid scratching; keep nails short and use a cool compress for brief relief. If a clinician identifies a trigger, record its name and where contact occurs. For recurrent rashes, photographs and a simple trigger diary can make follow-up more useful.

Itch, scaling, dryness, swelling, pain, warmth, fever or blisters can accompany a rash. The combination and sequence matter: for example, fever or rapidly increasing tenderness changes how urgently the skin should be assessed. Describe the full pattern rather than focusing on colour alone.

Many rashes improve once the trigger is removed or the underlying condition is treated. Others need a confirmed diagnosis and a longer prevention plan, particularly when they recur or affect sleep. Arrange review if the rash is spreading, returning, leaving pigment changes or failing to respond to the agreed care plan.