What should you know about lunula nail fungus?

The lunula is the lighter crescent near the base of some nails. Its shape and visibility naturally vary between fingers and toes. Nail fungus more often causes thickening, crumbling, yellow or white discolouration and separation from the nail bed, but early infection can be less obvious. Trauma, eczema, psoriasis, repeated wet work and other nail conditions can look similar.

Fungal infection may also occur with athlete’s foot because fungi can spread between skin and nails. A clinician may trim or scrape part of the nail for laboratory testing before choosing treatment.

Keep nails clean and dry, change damp socks, wear breathable footwear and avoid sharing clippers. Do not scrape beneath the nail or apply strong products without advice. A clinician may recommend a topical antifungal for limited disease or an oral antifungal when infection is more extensive; treatment choice depends on the nail, other medicines and liver health.

Laser treatment or nail surgery may be considered in selected situations, but neither replaces a careful diagnosis. Nail growth is slow, so improvement is judged as healthy nail grows from the base rather than by an instant colour change.

Arrange a medical review for a new dark streak, rapid nail change, pain, pus, marked swelling, or a nail that lifts without a clear injury. People with diabetes, poor circulation or reduced immunity should seek advice promptly for a painful or infected nail.

Ask whether the lunula change fits fungus or another nail condition, whether a sample should be tested, and how long treatment would be expected to continue. Discuss medicine interactions, warning signs of bacterial infection and ways to prevent spread to other nails or household members.