What should you know about vasculitis rash on feet?

Blood-vessel inflammation may produce pinpoint marks, larger purple patches, or raised spots on the feet and ankles. Burning, tenderness, swelling, or a bruised appearance can occur. A foot rash may also result from pressure, heat, sweat, footwear, allergy, infection, or irritation, so location alone cannot establish vasculitis.

Potential look-alikes include [Contact Dermatitis](/conditions/contact-dermatitis/) from shoes or products, [Heat Rash](/conditions/heat-rash/) from trapped sweat, and fungal [Ringworm](/conditions/ringworm/). [Atopic Dermatitis](/conditions/atopic-dermatitis/), [Psoriasis](/conditions/psoriasis/), [Intertrigo](/conditions/intertrigo/), [Scabies](/conditions/scabies/), and a [Drug Rash](/conditions/drug-eruption/) can also affect the feet or lower legs.

Photograph the feet in consistent light and note whether the marks fade when pressed, feel raised, itch, burn, or hurt. Record new shoes, exercise, illness, medicines, and products. Wash gently, dry carefully between the toes, avoid scratching, and pause any nonessential new product that touches the area.

Arrange a clinical examination rather than relying on photographs alone. The clinician may inspect the skin, check circulation and sensation, review medicines, and decide whether blood or urine testing or a skin sample is appropriate. Use only treatments recommended for the identified cause.

Seek urgent care for a rapidly spreading purple rash, severe foot pain, ulcers, blisters, blackening skin, fever, faintness, breathing difficulty, or swelling of the face or tongue. Prompt review is also needed if the rash comes with blood in the urine, severe abdominal pain, new numbness, or painful swollen joints.

Do the marks blanch or feel raised, and does that change the likely causes? Could footwear, infection, a medicine, or another skin condition explain the pattern? Do I need tests, a biopsy, or follow-up, and what changes should trigger urgent care?