Actinic Lichen Planus (lichen lanus tropicus)

Diagnosis: Actinic Lichen Planus (lichen lanus tropicus)

Nummular patches with a hypopigmented zone surrounding a hyperpigmented center.

Clinical Presentation

Nummular patches with a hypopigmented zone surrounding a hyperpigmented center.

Clinical History

Submitted by Alaa Saad. Originally posted November 5, 2010.

Treatment

See case discussion.

Differential Diagnosis

• Drug-induced lichenoid eruption • Psoriasis (guttate) • Pityriasis rosea • Secondary syphilis • Eczema • Lichen nitidus • Lichenoid keratosis • Graft-versus-host disease

Key Learnings

• Remember the 6 P's: Pruritic, Purple, Polygonal, Planar (flat-topped), Papules, Plaques • Wickham striae (fine white lines on surface) are pathognomonic — best seen with dermoscopy • Koebner phenomenon: lesions at sites of trauma • Oral LP: most common mucosal form — reticular (lacy white striae) vs. erosive • Erosive oral LP has a small risk of SCC transformation — requires monitoring • Hepatitis C association varies geographically — screening recommended • Histology: interface dermatitis with band-like lymphocytic infiltrate, sawtooth rete ridges, Max Joseph spaces (civatte bodies)

Tags: actinic, lichen, planus, lanus, tropicus, alaa saad