Signs and symptoms of oral lichen planus affect the mucous membranes of the mouth.

Appearance

The lesions may appear as:

• Lacy, white, raised patches of tissues
• Red, swollen, tender patches of tissues
• Open sores

Location

These lesions may appear on the:

• Inside of the cheeks, the most common location
• Gums
• Tongue
• Inner tissues of the lips
• Palate

Pain or discomfort

The white, lacy patches may not cause discomfort when they appear on the inside of the cheeks. However, symptoms accompanying red, swollen patches and open sores may include:

• Burning sensation or pain
• Sensitivity to hot, acidic or spicy foods
• Bleeding and irritation with tooth brushing
• Inflammation of the gums (gingivitis)
• Painful, thickened patches on the tongue
• Discomfort when speaking, chewing or swallowing

Other types of lichen planus

If you have oral lichen planus, you may have lichen planus lesions affecting other parts of your body.

• Skin. Lesions usually appear as purplish, flat-topped bumps that are often itchy.

• Genitals. Lesions on the female genitalia often cause pain or burning and discomfort with intercourse. The lesions are usually red and eroded and occasionally appear as white areas. Lesions also can occur on male genitalia.
• Ears. Lichen planus of the ears can lead to hearing loss.
• Scalp. When skin lesions appear on the scalp — a rare condition — they may cause temporary or permanent hair loss.
• Nails. Though rare, lichen planus of the toenails or fingernails may result in ridges on the nails, thinning or splitting of nails, and temporary or permanent nail loss.
• Eyes. Rarely, lichen planus may involve the mucous membrane surfaces of the eyes, and can cause scarring and blindness.
• Esophagus. Lichen planus of the esophagus also is rare, but when it occurs, it may result in a narrowing of the esophagus or the formation of tightened, ringlike bands in the esophagus that can make swallowing difficult.

It's not known what causes oral lichen planus. However, T lymphocytes — certain white blood cells involved in inflammation — appear to be activated in oral lichen planus. Although it could indicate an immune disorder, more research is needed to determine the exact cause.

It's possible that, in some people, oral lichen planus may be triggered by certain medications, mouth injury, infection, or allergy-causing agents such as dental materials. However, these causes are not confirmed.

Some factors may increase your risk of developing oral lichen planus, such as having a disorder that compromises your immune system or taking certain medications, though more research is needed.

Severe cases of oral lichen planus may increase the risk of:

• Significant pain
• Weight loss or nutritional deficiency
• Stress or anxiety
• Depression
• Scarring from erosive lesions
• Secondary oral yeast or fungal infections
• Oral cancer