If you have itchy, flat bumps that look purple, gray, or brown, especially on the wrists, shins, or lower back, and lacy white lines inside your cheeks, show them to a dermatologist. Lichen planus affects about 0.5% to 1% of people, according to a 2024 review in the American Journal of Clinical Dermatology. It is not contagious. On brown and black skin it can look purple, gray, or brown instead of red, and the dark marks it leaves behind can last longer than the rash itself.
What lichen planus looks like on brown and black skin
The American Academy of Dermatology (AAD) puts it plainly: the bumps "are red to purple in lighter skin tones. People with darker skin tones may have purple, gray, or brown bumps" (AAD). They are shiny and flat-topped, and they usually show up on the inside of the wrists, the arms, the legs, or the lower back. Small bumps can merge into thicker plaques, most often on the shins and ankles (AAD symptoms page). The itch ranges from none at all to intense.
Look closely at a bump in good light. Many carry Wickham striae, which a 2023 report in Dermatology Reports describes as "thin, pearly white structures arranged in a reticular pattern" over the lesions. A dermatologist can check for them with a handheld magnifier called a dermatoscope.
The purple-to-brown tone has a reason. Inflammation damages the bottom layer of the skin, and pigment drops deeper into the skin, where it reads as violet. A 2024 review of lichenoid conditions in skin of color in the International Journal of Dermatology traces the color to this "pigment incontinence."
The dark spots afterward are part of the condition
When the bumps heal, many people are left with dark patches called post-inflammatory hyperpigmentation (PIH). The AAD says people with darker skin tones are more likely to develop PIH, that the spots do not harm your skin, and that "it can take months to years for the dark spots to fade completely" (AAD). In skin folds such as the armpits or the crease of the groin, a form called inverse lichen planus often leaves darkened skin behind once the rash clears.
These marks are often why people finally book a visit. Treat the active rash first: a review of PIH in skin of color in the Journal of Clinical and Aesthetic Dermatology says treatment "begins with management of the initial inflammatory condition," followed by topical lightening agents and daily sunscreen. Our guides to dark spots on Black skin and hyperpigmentation treatments that work on dark skin cover the options and what to avoid, since harsh products can irritate the skin and make the darkening worse.
Two variants described in darker skin
Lichen planus pigmentosus looks less like bumps and more like flat discoloration. A 2018 review in the International Journal of Dermatology describes "acquired dark brown to gray macular pigmentation located on sun-exposed areas of the face, neck, and flexures, commonly found in dark-skinned patients." The same review links it to hepatitis C, sun exposure, and contact with substances such as mustard oil and nickel, and calls treatment "difficult."
Common skin conditions are treated in primary care, and community health centers charge on a sliding scale that is often $0. Our directory of free and charitable clinics lists centers by state. A same-day telehealth visit is self-pay and cannot be billed to Medicaid or commercial insurance, so the clinic route usually costs less. If you need a prescription sooner than the next appointment:
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Actinic lichen planus is a rare, sun-triggered variant. A 2024 study of 16 patients with skin of color in Dermatology Practice & Concept describes it on sun-exposed skin like the forehead and face, with pigmented, ring-shaped, plaque, and uneven-color (dyschromic) forms, including a pigmented type that resembles melasma. If a facial patch flares after summer sun, tell your dermatologist.
Mouth, nails, scalp and genitals: why some spots need follow-up
Lichen planus inside the mouth usually shows up as lacy white lines or small white spots on the tongue and inner cheeks. Some people get painful sores, and spicy or acidic foods can sting (AAD). The AAD says oral lichen planus carries "a small, increased risk of developing cancer in your mouth," and that drinking alcohol, smoking, or chewing tobacco raises that risk further (AAD).
How small? A 2019 meta-analysis of 82 studies and 26,742 patients in Oral Oncology put the combined rate of cancer transformation at 1.14% for oral lichen planus, with higher risk for red, eroded sores, tongue involvement, tobacco, and alcohol. A 2021 analysis in the Journal of Oral Pathology & Medicine that used stricter diagnostic rules found 0.44%. Either way the risk is low, and it is the reason a 2024 clinical review says follow-up "is necessary" (Am J Clin Dermatol). Keep your dental and dermatology appointments, and get seen soon for a mouth sore that will not heal, one that grows or changes color, an area that thickens or hardens, or pain when swallowing.
In the nails, lichen planus can take the shine off, cause ridges, and thin and split the nail until it stops growing; some people lose nails permanently. The AAD advises seeing a dermatologist when you first notice nail changes. In a 2024 series of six patients with skin of color and nail lichen planus, all six had darkening at the base of the nail (Dermatol Pract Concept). On the scalp the condition is called lichen planopilaris, and it can cause permanent patches of hair loss, so early treatment matters. On the penis it can cause violet spots or ring-shaped rashes, and on the vulva purple or reddish-brown bumps with lacy white lines (AAD).
Get tested for hepatitis C
Lichen planus and hepatitis C show up together more often than chance would predict. A 2023 meta-analysis of 192 studies in the Journal of Clinical Medicine found hepatitis C was about 4 times more common in people with lichen planus than in comparison groups, with large differences from country to country. The AAD notes your dermatologist may check for it (AAD).
You do not need a skin rash to qualify for the test. The CDC recommends hepatitis C screening at least once in a lifetime for all adults 18 and older, and says direct-acting antiviral pills can cure most people in 8 to 12 weeks (MMWR, 2020). If you have never been tested, ask for a hepatitis C antibody test at the same visit.
When a medication is the cause
Some drugs cause a rash that looks like lichen planus, called a lichenoid drug eruption. The AAD lists diuretics used for blood pressure and heart disease, pain relievers, and malaria-prevention drugs (AAD). A 2023 review of 323 cases in the Journal of the European Academy of Dermatology and Venereology found the most common culprits were cancer immunotherapy drugs called checkpoint inhibitors, followed by tyrosine kinase inhibitors and anti-TNF biologics. The rash appeared about 15.7 weeks after starting the drug on average, so the link is easy to miss. Bring your full medication list, and do not stop a prescribed drug on your own; in that review the drug had to be stopped in only 26% of cases.
Treatment: what a dermatologist may prescribe
Skin lichen planus can clear on its own, and the AAD says many people see clearing after about a year, so mild cases may not need treatment (AAD). When itch, pain, or spreading makes treatment worthwhile, the usual first step is a prescription corticosteroid cream or ointment, which the AAD says can reduce swelling, color changes, and itch. For the mouth, a 2024 review names superpotent topical steroids as first-line treatment for flares (Am J Clin Dermatol).
If that is not enough, a dermatologist may add tacrolimus ointment or pimecrolimus cream, antihistamine pills for itch, steroid injections into thick plaques, a short course of steroid pills, light therapy two to three times a week, or acitretin, an oral retinoid that must not be used in pregnancy, with no pregnancy for 3 years after stopping (AAD). Newer options under study for stubborn cases include JAK inhibitors such as tofacitinib, apremilast, and biologics that target IL-23 and IL-17 (Am J Clin Dermatol). At home, avoid scrubbing or injuring the skin, since the AAD notes that irritation can trigger new bumps.
Diagnosis usually starts with an exam of your skin, scalp, nails, and mouth plus a review of your medications; some people need a small skin biopsy. If you want a dermatologist who sees skin like yours every day, search our dermatology directory.
Frequently asked questions
What does lichen planus look like on Black skin? ▼
Shiny, flat-topped bumps that often look purple, gray, or brown rather than red, sometimes with fine white lines on top (Wickham striae).
Is lichen planus contagious? ▼
No. You cannot catch lichen planus from someone else or give it to anyone.
What is lichen planus pigmentosus? ▼
A variant that causes flat dark brown to gray patches on the face, neck, and skin folds. A 2018 review describes it as commonly found in people with dark skin. A biopsy may be needed to tell it apart from melasma.
Will the dark spots from lichen planus go away? ▼
They often fade, but the AAD says it can take months to years. Treat the active rash first, then use daily sunscreen.
Can lichen planus turn into cancer? ▼
Oral lichen planus carries a small increased risk of mouth cancer, about 1% in one large meta-analysis, so keep regular dental and dermatology checks.
Is lichen planus linked to hepatitis C? ▼
Yes. Hepatitis C is more common in people with lichen planus, and the CDC recommends every adult get tested at least once.
