Onychomycosis (distal and lateral subungual type)

Diagnosis: Onychomycosis (distal and lateral subungual type)

The side of the toenail is discoloured yellow with onycholysis.

Clinical Presentation

The side of the toenail is discoloured yellow with onycholysis.

Clinical History

Submitted by Alaa Saad. Originally posted October 12, 2010.

Treatment

See case discussion.

Differential Diagnosis

• Psoriatic nail disease • Lichen planus (nail) • Nail trauma/dystrophy • Yellow nail syndrome • Melanonychia • Squamous cell carcinoma of nail unit

Key Learnings

• Confirm diagnosis before treating — nail clipping for PAS stain is most sensitive; KOH and culture also used • Distal/lateral subungual onychomycosis (DLSO) is the most common pattern — caused by T. rubrum • White superficial onychomycosis: T. mentagrophytes — white, crumbly nail surface • Proximal subungual onychomycosis: uncommon — consider HIV testing • Oral terbinafine has highest cure rates (~70-80%) — liver function monitoring recommended • Topical efinaconazole 10% and tavaborole 5% for mild disease without matrix involvement • Dermatophytoma (thick keratotic mass within nail plate) is resistant to medical therapy — may need avulsion

Tags: onychomycosis, distal, and, lateral, subungual, type, alaa saad