Lichen planus vs Lichen sclerosus
How to tell Lichen planus and Lichen sclerosus apart when a board question makes them look alike.
Lichen planus is purple pruritic polygonal papules with Wickham striae; lichen sclerosus is white atrophic vulvar sclerosis with SCC risk.
Side by side
Lichen planus causes pruritic purple polygonal planar papules and plaques, Wickham striae, oral lacy lesions, and band-like lymphocytic infiltrate.
Lichen sclerosus causes thin white atrophic plaques, often vulvar with figure-eight distribution, pruritus, scarring, and increased vulvar squamous cell carcinoma risk.
T-cell-mediated interface dermatitis damages basal keratinocytes.
Chronic inflammatory dermatosis causes dermal sclerosis and epidermal atrophy in anogenital skin.
Wickham striae, sawtooth lymphocytes, and oral mucosal involvement support lichen planus.
Porcelain-white atrophic vulvar plaques and dermal sclerosis support lichen sclerosus.
The trap
Both are lichenoid and itchy, so color, mucosal pattern, anatomic site, and cancer risk separate them.
The repair move
For lichenoid dermatoses, use color, site, mucosal pattern, and atrophy/sclerosis.
Try a free question
CoreA 38-year-old woman has 6 weeks of pruritic, purple, polygonal, flat-topped papules on the wrists and ankles, with fine white lacy lines on the surface (Wickham striae). The buccal mucosa shows similar reticulated white lacy patches. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Lichen planus. Lichen planus features the 6 P's: pruritic, purple, polygonal, planar, papules, and plaques, with Wickham striae and reticulated oral mucosal patches; associated with hepatitis C, drugs (gold, antimalarials, thiazides); treatment is topical corticosteroids.
Why the other choices are tempting
- B. Lichen sclerosus is white atrophic patches typically on the vulva or penis without purple polygonal papules.
- C. Pityriasis rosea has a herald patch followed by Christmas tree pattern on the trunk.
- D. Psoriasis has silvery scaly plaques on extensor surfaces.
- E. Discoid lupus has erythematous plaques with adherent scale, follicular plugging, and scarring on sun-exposed areas.
Flashcards
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What oral finding supports lichen planus?
Wickham striae support lichen planus.
What cancer risk follows lichen sclerosus?
Vulvar squamous cell carcinoma risk increases in lichen sclerosus.
Quick answers
What is the fastest way to tell Lichen planus from Lichen sclerosus?
Lichen planus is purple pruritic polygonal papules with Wickham striae; lichen sclerosus is white atrophic vulvar sclerosis with SCC risk.
What is the key clue for Lichen planus?
Lichen planus causes pruritic purple polygonal planar papules and plaques, Wickham striae, oral lacy lesions, and band-like lymphocytic infiltrate.
What is the key clue for Lichen sclerosus?
Lichen sclerosus causes thin white atrophic plaques, often vulvar with figure-eight distribution, pruritus, scarring, and increased vulvar squamous cell carcinoma risk.
What is the common trap with Lichen planus vs Lichen sclerosus?
Both are lichenoid and itchy, so color, mucosal pattern, anatomic site, and cancer risk separate them.