Onychomycosis (distal subungual type)

Diagnosis: Onychomycosis (distal subungual type)

Yellow-white discoloration of the nail plate and subungual hyperkeratosis with onycholysis.

Clinical Presentation

Yellow-white discoloration of the nail plate and subungual hyperkeratosis with onycholysis.

Clinical History

Submitted by Alaa Saad. Originally posted September 22, 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, subungual, type, alaa saad