What should you know about red blemishes on skin?

Flat redness after a new product or fabric exposure can fit Contact Dermatitis. Itchy rough patches may occur with Psoriasis or another inflammatory condition, while heat and sweat can produce Heat Rash. Redness after strong sun exposure may be Sunburn. Facial flushing and small bumps can occur with Rosacea. A hot, tender area that expands, especially with fever or feeling unwell, needs assessment for Cellulitis. These patterns overlap, so a blemish is not a diagnosis by itself.

Clean gently with lukewarm water, pat dry, and use a simple moisturiser. Pause recently introduced cosmetics, detergents, or fragranced products. Protect exposed skin from further sun and heat, and avoid picking, harsh exfoliation, and unlabelled combination creams. Take a clear photograph and record onset, exposures, itch, pain, warmth, scale, discharge, and spread. If redness persists or recurs, a clinician can examine it and decide whether testing or targeted treatment is needed.

Seek urgent help for breathing difficulty, swelling of the face or mouth, faintness, extensive blistering, skin peeling, or a rapidly spreading reaction. Obtain prompt medical care for increasing warmth or pain, pus, fever, red streaks, or redness near the eye. Arrange a dermatology review for a persistent blemish, a sore that does not heal, or a changing area that concerns you.

Which features point toward Contact Dermatitis, Rosacea, Psoriasis, or infection? Should I stop a product or medicine? Is a swab, scraping, or other examination useful? What change would require urgent care?