How effective is topical antifungal treatment for nail fungus?

Nail fungus, or onychomycosis, can make a nail thick, discoloured, brittle or separated from the nail bed. A topical medicine reaches the nail surface and may be suitable when infection is limited or oral medicine is not appropriate. The old damaged part does not instantly become clear; visible improvement comes as unaffected nail grows from the base.

Have the diagnosis checked before committing to a long course, since trauma and skin conditions can resemble nail fungus. Apply the medicine as directed to a clean, dry nail, keep nails trimmed and do not share clippers. Keep feet dry, change socks when damp and treat coexisting athlete's foot if advised, because it can re-seed the nail.

Arrange an assessment if several nails are affected, the nail is painful, the surrounding skin is inflamed, or there is no visible healthy growth after consistent treatment. People with diabetes, poor circulation or a weakened immune system should seek tailored advice promptly for foot or nail changes.

Does the nail change need testing? Is topical treatment suitable for the depth and area involved? How will we judge progress, and should nearby foot skin be treated too?