Onychomycosis

Facts about Onychomycosis

  • Onychomycosis is very common. 50% of patients older than 70 years old have it.
  • Onychomycosis is most often caused by dermatophytes of the genus Trichophyton. Non-dermatophyte molds are less common.
  • Treating onychomycosis is more than just about cosmetics. It can lead to cellulitis in the elderly, and foot ulcers in diabetics.
  • Onychomycosis is hard to treat, since it’s difficult for drugs to get to the nails. You may not see results for a year with treatment, and recurrence rate is high (10-53%).
  • Mycotic cure = cure of the fungus itself. Clinical cure = when the nail cosmetically looks better.

First Things First

  • Only 50% of nail problems are caused by onychomycosis, so diagnosis by physical exam is not enough. Need to do labs first. Clean nails with alcohol and do office microscopy of the nail clippings using KOH. If you don’t see fungus, then do fungal culture or histologic evaluation with periodic acid-schiff (PAS) staining. If positive, then treat. If negative, think of psoriasis, chronic nail trauma, or other non-fungal causes.
  • Don’t use oral agents in those with liver, renal, or heart disease. Do LFTs before beginning treatment, and 1 month after therapy. Risk of asymptomatic elevated LFTs is 2%.
  • Continue nail trimming, debridement, and hygiene while getting treatment. Frequent dark, moist environments, like shoes increase risk of nail fungus. Consider wearing sandals.

Oral Medications

  • Terbinafine (Lamisil) – 250mg PO qday x12 wks. Mycotic cure rate 76%, clinical cure rate 66%. $4/month generic. Use for yeasts, dermatophytes, non-dermatophyte molds. Overall, cheapest and most effective.
  • Itraconazole (Sporanox) – [Pulse dosing: 200mg PO BID x1 wk/mo x3 months] Mycotic cure rate 63%, clinical cure rate 70%. [Continuous dosing: 200mg qday x12 wks] Mycotic cure rate 59%, clinical cure rate 70%. $195/month generic. Use for Candida, dermatophytes, non-dermatophyte molds, Aspergillus.

Topical Medications

  • Ciclopirox – Only topical med available in US for onychomycosis. Use for those who can’t take PO meds, and who have milder cases. Mycotic cure rate 29%, Clinical cure rate 6%. Can use in combo with PO meds for increased effectiveness. $11 per month. Use for Candida, dermatophtes.

Complementary Medicine – only small studies have been done on these. Use with caution.

  • Vicks Vaporub – Small study showed mycotic and clinical cure rate of 28%.
  • Ageratina pichinchensis (Snakeroot Extract) – Small study shows mycotic cure rate of 59% and clinical cure rate of 71%.
  • Cyanoacrylate/Undecylenic Acid/Hydroquinone (Renewed Nail) – small study shows mycotic cure rate of 50%.

 

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