When should you see a doctor about rash with fever?

A fever means the body is responding to inflammation or infection. The rash may be flat, raised, blistered, painful, or involve peeling skin. Cellulitis can cause a hot, tender, expanding area, while chickenpox often produces an itchy rash that changes into fluid-filled spots. A new medicine can trigger a drug rash. A painful rash with blisters, mouth or eye involvement, or skin peeling needs particularly careful assessment because Stevens-Johnson Syndrome is one possible emergency.

Note when the fever and rash began, where the rash started, how it has changed, and any new medicines, foods, products, travel, or sick contacts. Take clear photographs in good light. Drink fluids if you can, rest, and avoid scratching or applying a new cream until a clinician advises you. Do not stop a prescribed medicine without checking, but contact a clinician promptly if the rash began after a new dose.

Go to emergency care for trouble breathing, swelling of the lips or tongue, faintness, confusion, a very severe headache, stiff neck, purple or bruise-like spots, severe pain, skin peeling, or sores in the mouth or eyes. Seek same-day assessment for a rapidly spreading rash, persistent vomiting, marked weakness, dehydration, or fever in a very young child or someone with reduced immunity. A clinician can examine the pattern and decide whether tests or treatment are needed.

Could this be an infection or a reaction to a medicine? What warning signs should make me return urgently? Should I avoid any products, medicines, or close contact while the cause is being assessed?