Overview
Onychomycosis is usually caused by dermatophyte fungi spreading from athlete's foot into the nail plate. The infection sits under the nail, which is why creams designed for skin do not work.
Risk increases with age, diabetes, poor circulation, nail trauma, communal changing rooms and occlusive footwear. Not all thickened or discoloured nails are fungal - psoriasis and trauma can look identical.
When to seek urgent medical help
- • Diabetes, poor circulation or numbness in the feet with a nail infection
- • Surrounding redness, pain, pus or spreading swelling
- • A single dark streak or pigment change in one nail
Symptoms and signs
- White, yellow or brown discolouration of the nail
- Thickened, crumbly or brittle nail edges
- Nail lifting away from the nail bed
- Distorted nail shape and debris beneath the nail
- Associated scaling or itching between the toes
- Discomfort in shoes when the nail thickens
Management and treatment
Mild infection affecting less than half of one or two nails can be treated topically. More extensive disease, matrix involvement or toenails generally require oral terbinafine, which is far more effective but needs liver function checks.
Your ChatDoc doctor assesses the extent from your photos, advises whether nail sampling is needed and prescribes the treatment and monitoring plan that fits.
Prescription treatment options
Amorolfine nail lacquer
Weekly topical treatment for limited infection, used for 6-12 months.
Oral terbinafine
Most effective option: 6 weeks for fingernails, 12 weeks for toenails, with liver monitoring.
Itraconazole pulse therapy
Alternative oral treatment where terbinafine is unsuitable.
Footcare and reinfection prevention
Treating athlete's foot, disinfecting footwear and nail-filing advice to stop recurrence.
Any prescription is issued only after a doctor has reviewed your case and considers the treatment safe and appropriate for you.
Your online Fungal Nail Infection assessment
- 1
Tell us about your concern
Share symptoms, past treatments, medicines and relevant health information.
- 2
Upload clear photos
Upload photos of your concern where applicable.
- 3
Doctor reviews your case
Technology helps organise your answers, but every assessment and prescription decision is made by a doctor, who may message you if they need more information.
- 4
Get your personalised plan
A personalised prescription is issued if treatment is clinically appropriate.
Prognosis and outlook
Nails grow slowly, so appearance improves over 6-12 months even when treatment works. Cure rates are around 70-80% with oral treatment and 20-40% with topical treatment alone.
Recurrence is common without footcare, so prevention measures continue after the nail has cleared.
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This page is general medical information and does not replace a personal consultation. Always seek urgent care for severe or rapidly worsening symptoms. ChatDoc is not an emergency service. Call 999 (UK) or 112 (EU) for life-threatening emergencies or 111 for urgent non-emergency help. Do not wait for an online reply.