Pterygium of nail - Lichen planus

066. Pterygium of nail is characteristically seen in:

1. Lichen planus

2. Psoriasis

3. Tinea unguium

4. Alopecia areata

Answer

1. Lichen planus

Reference

Rook’s text book of Dermatology Chapter 65 – Diseases affecting the nails

Quality

Reader

Status

Repeat

Discussion

As per Rook’s textbook of Dermatology, pterygium of nail (pterygium unguis) is the fusion of eponychium with proximal portion of nail.

Explanation

Lichen Planus can involve the proximal nail folds with bluish-red discoloration. Nail-plate changes include thinning, onychorrhexis, brittleness, crumbling or fragmentation, and accentuation of surface longitudinal ridging. All these features are secondary to disease affecting the matrix, which can also produce transient or permanent longitudinal melanonychia or leukonychia as a postinflammatory phenomenon

When inflammation is intense and widespread within the nail apparatus, nails may be shed.

Single longitudinal depressions in the nail, with a distal notch or entire split may arise from a pterygium. This is a fibrotic band of tissue fusing the proximal nail fold with the nail bed and matrix following destructive local inflammation. Surviving proximal matrix is unable to push growing nail through the scar tissue, with a consequent split.

Comments

Nail-bed disease can produce subungual hyperkeratosis and onycholysis. Bullous lichen planus may affect the soles of the feet and in particular the toenails. Permanent anonychia may follow

Tips

Lichen planus nail changes are seen in graft-versus-host disease and in the disseminated lichenoid papular dermatosis of AIDS. There can be an overlap between lichen planus and discoid lupus erythematosus both in the skin and in the nails.