Lichen planus: Signs and symptoms

You may see red (A), purple (B), gray (C), or brown bumps. These bumps can appear anywhere on your skin but usually develop on the inside of the wrists, arms, legs, or lower back.

Sometimes, small bumps merge to form a larger area called a plaque. When plaques form, they usually develop on the shins and ankles.

Not everyone develops itchy skin, but for some the bumps itch. The itch ranges from mild to intense.

Some people develop dark spots called post-inflammatory hyperpigmentation (PIH). People who have a darker skin tone are more likely to develop PIH. These dark spots do not harm your skin and often go away in time. However, it can take months to years for the dark spots to fade completely.

Some people develop a rash only on an area of their body where skin touches skin, such as an armpit (A), bend in the elbow or knee, crease where the leg meets the trunk, or under a breast. This is called inverse lichen planus. When the rash clears in one of these areas, darkened skin often develops (B).

When lichen planus affects the mouth, it’s called oral lichen planus. Inside the mouth, it can develop on your cheeks, gums, tongue, or the roof of your mouth. It occasionally appears on the lips. On the tongue and insides of the cheeks, it usually causes lacy, white lines (A) or crops of small white spots (B).

Inside your mouth, you have swelling and a violet or red color. Some people develop painful sores, which can appear on the gums, tongue, or roof of the mouth. Others say their mouth feels tender or burns. These symptoms can make eating painful, especially if you eat spicy or acidic foods.

When this disease develops on the scalp, it’s called lichen planopilaris, or LPP. LPP often begins with small bumps on the scalp, and the scalp may feel irritated. Some people notice that their scalp feels tender or burns. Occasionally, hair thins. Some people develop patches of hair loss.

When lichen planus appears on the nails, it may affect one, a few, or all 20 nails. The affected nails lose their shine. Grooves and ridges can appear. Seeing a board-certified dermatologist for treatment when you first notice nail changes can avoid further changes.

As the disease progresses, the affected nails become thinner and start to split. Nails may stop growing. Some people permanently lose one or more nails.

When lichen planus develops on the genitals, it can cause a rash, along with soreness, burning, itching, or pain. On the vulva and soft, moist tissue that lines the vagina, this condition can cause purple or reddish-brown bumps and lacy-looking white lines. Lichen planus on the penis can cause violet spots or ring-shaped rashes.