Lichen planus - Anogenital in
See oral lichen planus for oral mucosal presentation and lichen planopilaris for scalp presentation.
Certain medications may cause a lichenoid drug eruption, which is indistinguishable from typical LP.
L43.9 – Lichen planus, unspecified
4776004 – Lichen planus
Differential Diagnosis & Pitfalls
- Psoriasis – Look for psoriasis at other classic body sites.
- Lichenoid drug eruption – The mucocutaneous eruption is widespread.
- Seborrheic dermatitis (genital lesions) – Look for well-demarcated plaques with greasy scale.
- Lichen sclerosus (vulvar lesions) – Look for porcelain white atrophic plaques with areas of hemorrhage.
- Lichen simplex chronicus – Look for lichenification with exaggerated skin markings on glabrous areas of vulva only, often with excoriations.
- Vulval candidiasis – Also itchy; outlying satellite papules and pustules are a diagnostic hallmark.
- Tinea cruris – Look for annular, scaly plaques.
- Pemphigus vulgaris – Look for erosions and blisters with positive Nikolsky's sign, Asboe-Hansen sign.
- Secondary syphilis – Condyloma lata are moist, gray papules and plaques.
- Mucous membrane pemphigoid – Look for blisters and erosions, scarring, and stricture formation in later stages.
- Desquamative inflammatory vaginitis – Look for mucosal erythema, edema, erosions, and discharge.
- Plasma cell vulvitis – Look for well-circumscribed violaceous plaque, often on the vestibule.
- Erythema multiforme – Look for skin with target lesions, mucosal ulcers, and hemorrhagic crust.
- Squamous cell carcinoma – A well-demarcated scaly or hyperkeratotic plaque, or a nonhealing erosion.
- Papular acantholytic dermatosis
- Bullous pemphigoid
- Recessive dystrophic epidermolysis bullosa (vulvar lesions)
- Junctional epidermolysis bullosa (vulvar lesions)
Drug Reaction Data