Thick, yellow, crumbly toenails that won’t clear up? That’s likely a fungal nail infection (onychomycosis). It’s common, stubborn, and slow to treat — but with consistent care, smart footwear and hygiene habits, you can get healthier nails and keep them that way.
This guide explains causes, symptoms, fungal toe nail treatment options, prevention, and the shoe/sock routines that matter most.
What Is a Fungal Nail Infection?
Onychomycosis is a fungal infection of the nail plate and nail bed, most often caused by dermatophytes (the same family that causes athlete’s foot). It typically starts at the nail edge and creeps inward, making nails thick, discoloured, and brittle.
Causes and Risk Factors
- Untreated or recurrent athlete’s foot spreading to the nails
- Warm, damp shoe environments (sweaty feet, non-breathable footwear)
- Nail trauma from tight toe boxes or long nails hitting the shoe
- Ageing, diabetes, poor circulation, or reduced immunity
- Walking barefoot in communal areas (pools, locker rooms)
Symptoms and How to Recognise Them
- Yellow, brown, or white discolouration starting at the edge
- Nail thickening, crumbling, or flaky debris under the nail (subungual debris)
- Nail shape distortion, lifting from the nail bed (onycholysis)
- Mild odour; sometimes discomfort in shoes due to nail bulk
Why Footwear Matters
Nails improve faster when the environment is dry, spacious, and low‑friction. Tight or sweaty shoes damage the nail and feed fungus.
- Wide, deep toe boxes to avoid nail trauma
- Breathable uppers (mesh/leather) and moisture‑wicking socks
- Rotate footwear to dry 24–48 hours between wears
- Removable insoles so you can air/replace them and use antifungal powder
References
- NHS – Fungal nail infection overview
- NICE CKS – Fungal nail infection: Prevalence
- Sigurgeirsson B, et al. (2020). Prevalence of onychomycosis in the general population: A systematic review. J Eur Acad Dermatol Venereol
Fungal Toe Nail Treatment Options
At‑home & over‑the‑counter
- Topical antifungals (lacquers/solutions) applied daily or weekly depending on product
- Nail care routine: trim nails straight, thin thick nails gently with a file, clean debris
- Antifungal sprays/powders for shoes and between toes to prevent reinfection
Prescription options (talk to your clinician)
- Oral antifungals (e.g., terbinafine, itraconazole) — higher cure rates but require medical suitability and monitoring
- Prescription topical solutions for mild/moderate cases or when pills aren’t suitable
- Combination therapy (oral + topical + nail debridement) for stubborn infections
What results to expect
- Nails grow slowly — expect 3–6 months for visible improvement and up to 12–18 months for full regrowth of big toenails
- Clearing starts at the base (new nail) and advances towards the tip
Prevention & Hygiene Tips
- Treat athlete’s foot promptly to protect nails
- Change socks daily (twice if sweaty); use moisture‑wicking fabrics
- Alternate shoes; use antifungal powder in shoes during treatment
- Keep nails short (not too short) and filed smooth to reduce shoe impact
- Wear flip‑flops in communal showers/pools; don’t share nail tools
- Disinfect nail clippers/files; consider separate tools for affected nails
Best Footwear for Fungal Nails
Prioritise:
- Roomy width & toe height to avoid pressure on thick nails
- Breathable uppers and removable insoles
- Moisture‑wicking socks; avoid plastic‑coated, non‑breathable styles
- Easy‑clean surfaces if you’re using shoe disinfectant sprays
When to See a Doctor or Podiatrist
- You’re unsure it’s fungus (e.g., trauma or psoriasis can look similar)
- Multiple nails are involved, or there’s pain or ingrown nails
- You have diabetes, poor circulation, or immunosuppression
- No improvement after several months of correct treatment
FAQs
Q: Do I need oral tablets or will topicals work?
A: Mild infections may respond to topicals, but thick/multiple‑nail infections often need oral medication. Your clinician can advise based on nail appearance and medical history.
Q: Can I wear nail polish?
A: Best avoided during active treatment with topicals unless using a breathable polish approved for use with antifungal lacquers. Polish can trap moisture and hide progression.
Q: Will shoes reinfect my nails?
A: They can — spray or powder the insides regularly during treatment and rotate pairs to dry fully.
Q: How long does it take to cure?
A: Expect months, not weeks. New, clear nail grows from the base; full big‑toe replacement can take up to a year or more.
I have suffered with a fungal nail infection on my right hand big toe. Following ankle surgery in January 2025, I noticed that it began to improve without treatment. When I was discharged from hospital my foot was covered in povidone iodine stain that was applied prior to surgery as an antiseptic. I have since read that Iodine does in fact have some anti fungal properties. It may be worth a try.
Related Reading
Treat the nail, treat the skin, treat the shoes — that’s the trifecta. Stay consistent and patient, and you’ll see healthier nail grow‑out month by month.