What should you know about erythema marginatum causes?

The border may expand while the centre becomes less red, and the pattern can be easier to see on some skin tones than others. A clinician considers timing, itch, pain, scale, warmth, recent products, sun exposure, medicines, and other symptoms. Similar redness can occur with [Contact Dermatitis](/conditions/contact-dermatitis/), [Heat Rash](/conditions/heat-rash/), [Psoriasis](/conditions/psoriasis/), [Rosacea](/conditions/rosacea/), or [Sunburn](/conditions/sunburn/). A hot, tender, rapidly enlarging area needs a different assessment, including for [Cellulitis](/conditions/cellulitis/).

Take a clear photograph in good light and note when the redness began, whether it moves or fades, and any new products, medicines, illness, heat, or sun exposure. Avoid new fragranced products and strong exfoliation until the cause is clearer. Do not diagnose from the ring shape alone. A dermatologist can decide whether observation, treatment of an underlying condition, or a procedure such as [IPL Photofacial](/treatments/laser-and-energy/ipl-photofacial/) is appropriate after diagnosis.

Seek prompt medical care if redness is rapidly spreading, hot, swollen, or painful, or if you have fever or feel unwell. Get urgent help for facial swelling, breathing difficulty, blistering, skin peeling, confusion, or faintness. A mild, stable rash can still need a routine appointment if it persists, recurs, or remains unexplained.

Does the shape fit a specific diagnosis? Could a medicine, contact exposure, heat, or sun be involved? What changes would mean I need urgent review?