Lichen Planus vs Psoriasis

How to tell the difference — key features compared side by side.

Feature
Lichen Planus
Psoriasis
Category
Common
Common
Key feature
Purplish, flat-topped, itchy bumps - the five Ps: Pruritic, Purple, Polygonal, Planar, Papules.
Chronic autoimmune condition causing thick, silvery scaly patches. Affects 2-3% of the population. Not contagious.
Risk factors
Middle age (most common ages 30-60); Hepatitis C infection (associated); Certain medications
Family history of psoriasis (strongest risk factor); Stress (major trigger for flares); Obesity
Action needed
Itchy purple bumps, especially on wrists or ankles
Persistent thick, scaly patches that do not respond to moisturizers

Lichen Planus

Lichen planus is an inflammatory condition that causes distinctive purplish, flat-topped, polygonal (angular) papules that are characteristically itchy. The classic presentation is remembered by the five Ps: Pruritic (itchy), Purple, Polygonal, Planar (flat-topped), Papules.

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Psoriasis

Psoriasis is a chronic autoimmune condition in which the immune system mistakenly accelerates skin cell growth. Normal skin cells mature and shed in about a month; in psoriasis, this process takes only 3-4 days, causing cells to pile up into thick, silvery-white scales on red, inflamed patches.

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Does yours look more like lichen planus?

Quick self-check

Does this look like lichen planus? Answer 2 questions.

Are the bumps purple, flat-topped, and angular (polygonal) in shape?

Are they on the wrists, ankles, or inside the mouth?

Still not sure?

Our full ABCDE checker evaluates 5 clinical criteria dermatologists use.

Full ABCDE check →