Do yellow nails mean a fungal infection, and how are they treated?
Yellow nails can result from polish, injury, fungi or skin disease; colour alone does not establish the cause. Thickening, crumbling, separation and pain help guide assessment. Antifungal treatment, particularly tablets, should not be started solely because a nail is yellow.
Details
Why might a nail sample be taken?
Testing a nail clipping can confirm infection before prolonged treatment, because psoriasis and trauma can resemble fungi. Topical versus oral treatment depends on severity, affected nails, health and drug interactions.
Normal growth takes time
Improvement appears as new nail grows; colour does not change immediately. Keep feet dry and trim nails without injury. Avoid sharing clippers, removing nails yourself or applying caustic substances.
When is faster review needed?
Increasing pain, redness, swelling or pus needs assessment, especially with diabetes, reduced immunity or poor circulation. Changes in several nails or a new distinct dark band warrant examination rather than an automatic fungal diagnosis.
Related reading: Do white spots on nails indicate calcium deficiency?.