Lichen planus (LIE-Kun PLAY-Nus) is a condition that can cause swelling and irritation in the skin, hair, nails, and mucous membranes. On the skin, lichen planus usually appears as purplish, itchy, flat bumps that develop over several weeks. In the mouth, vagina, and other areas covered by a mucous membrane, lichen planus forms lacy white patches, sometimes with painful sores.
Causes
Lichen planus occurs when your immune system attacks cells of the skin or mucous membranes. It’s not clear why this abnormal immune response happens. The condition isn’t contagious.
Lichen planus can be triggered by:
- Hepatitis C infection
- Flu vaccine
- Certain pigments, chemicals, and metals
- Pain relievers, such as ibuprofen (Advil, Motrin IB, others) and naproxen (Aleve, others)
- Certain medications for heart disease, high blood pressure, or arthritis
Symptoms
The signs and symptoms of lichen planus vary depending on the areas affected. Typical signs and symptoms are:
- Purplish, flat bumps, most often on the inner forearm, wrist, or ankle, and sometimes the genitals
- Itching
- Blisters that break to form scabs or crusts
- Lacy white patches in the mouth or on the lips or tongue
- Painful sores in the mouth or vagina
- Hair loss
- Change in scalp color
- Nail damage or loss
When to see a doctor
See your doctor if tiny bumps or a rash-like condition appears on your skin for no apparent reason, such as a known allergic reaction or contact with poison ivy. Also see your doctor if you experience any signs or symptoms associated with lichen planus of the mouth, genitals, scalp, or nails.
It’s best to get a prompt and accurate diagnosis because different skin and mucosal conditions can cause lesions and discomfort.
