Lichen planus is an inflammatory condition affecting the skin, hair, nails, and mucous membranes, causing itchy, purple, flat-topped bumps on the skin and lacy white patches or sores in the mouth. The exact cause is unknown but is thought to be an autoimmune reaction, possibly triggered by factors like hepatitis C, certain medications, or stress. Treatment focuses on managing symptoms with topical steroids for mild cases or more intensive systemic treatments for severe cases.

Symptoms

• Skin: Itchy, purple or reddish-purple, flat-topped bumps that can appear on the wrists, lower back, and ankles. Thick, scaly patches may also develop on the shins and ankles.
• Mouth: Lacy white patches are common, sometimes accompanied by painful sores that can make it difficult to eat.
• Genitals: Tiny, raised dots can appear.
• Nails: The nail plate can become thin, cracked, or split. The nail may also darken, stop growing, or lift off the nail bed.

Causes and triggers

• Autoimmune reaction: The body's immune system mistakenly attacks skin and mucous membrane cells.

• Infections: Hepatitis C is a known trigger.
• Medications: Certain high blood pressure, diabetes, and heart medications can be triggers.
• Allergies: Allergic or immune reactions to certain chemicals, metals, and dyes are possible causes.
• Genetics: A family history can play a role.
• Stress: Stress can be a trigger for an outbreak.

Treatment

• Mild cases: May not require treatment, or topical treatments like strong steroids can be used for less than 20% of the body.
• Severe cases: Require more intensive therapy, which may include systemic corticosteroids, other drugs like cyclosporine or methotrexate, and phototherapy.
• Oral lichen planus: Treatment focuses on symptom relief, as there is no cure. You may not need treatment if there are no painful sores.