What should you know about thick yellow toenails?

Fungal nail disease can thicken the nail and cause yellow, cream, or brown discolouration, with crumbly edges or material underneath. Repeated pressure from footwear may thicken one nail and change its colour after small injuries. Nail psoriasis may produce ridges, pits, lifting, or a yellow-brown patch. A colour change is a clue, not a diagnosis.

A clinician may look at all toenails, the surrounding skin, and your footwear habits. Nail testing can help distinguish fungus from inflammatory or mechanical causes before a longer course of treatment is chosen.

Wash and dry your feet, especially between the toes. Wear socks that keep moisture away and shoes that do not press on the nail. Trim straight across with clean tools, avoid picking at debris, and do not share clippers or towels. Treating peeling skin promptly can help limit spread between the foot and nails.

If fungus is confirmed, options may include a prescribed topical medicine or [Oral Antifungal Treatment](/treatments/medical-dermatology/oral-antifungal-therapy/). A clinician may also explain whether [Laser Treatment For Nail Fungus](/treatments/laser-and-energy/laser-nail-fungus-treatment/) is appropriate for your situation.

Arrange care when yellow thickening persists, affects several nails, or makes shoes uncomfortable. Seek prompt help for spreading redness, warmth, swelling, drainage, severe tenderness, or a new dark mark. Do not self-manage a foot wound if you have diabetes, reduced sensation, or poor circulation; contact a healthcare professional instead.

Ask whether the appearance fits [Nail Fungus](/conditions/nail-fungus/) or [Nail Psoriasis](/conditions/nail-psoriasis/), whether a nail sample should be taken, and how your health history affects medicine choices. Ask how to reduce shoe pressure while the nail grows.