What should you know about terbinafine skin rash?

Skin changes during treatment can come from the infection, irritation, another medicine or a reaction to terbinafine. A photo, the date the rash began and a list of all products can help the clinician judge the pattern. Do not assume that every red patch has the same cause.

A mild, localised rash still deserves advice about whether to continue. A rapidly spreading rash, target-like spots, blisters, peeling skin or sores in the mouth or eyes can represent a severe medicine reaction and needs urgent assessment.

Contact the prescriber or pharmacist and describe where the rash started, how quickly it changed, and whether you have itching, fever, swelling or pain. Keep the package and medication list available. Avoid adding a new cream that could obscure the appearance unless a clinician recommends it.

For background on the medicine, read [Terbinafine](/materials/terbinafine/) and [Oral Antifungal Treatment](/treatments/medical-dermatology/oral-antifungal-therapy/). Follow direct instructions about pausing or restarting treatment; do not double a dose after an interruption.

Seek urgent medical care for blistering, skin peeling, painful raw areas, widespread redness, sores on the lips or inside the mouth, eye involvement, fever with a rash, or swelling of the face or tongue. Trouble breathing, faintness or throat tightness is an emergency.

Until you receive advice, avoid further doses if a healthcare professional has told you to stop. If symptoms are severe, take the medicine packaging with you and do not wait for the rash to settle on its own.

Ask whether the rash could be a medicine reaction, whether terbinafine should be paused, what alternative treatment might be appropriate, and which changes require emergency care.