Is Lichen Planus an Autoimmune Disease?
Lichen planus is a T-cell mediated autoimmune disease. The T-cells identify the normal cells in the skin and mucous membranes of various parts of the body as faulty cells. Therefore, the T-cells activate and destroy these cells. This will cause the lesions in the body. It mainly occurs in the oral cavity. Other than that it also occurs in the skin, genital tract, nails, ears, scalp, eyes and esophagus. Lichen planus (LP) is a chronic inflammatory disease that affects the skin and mucous membranes. It is an autoimmune disease. It is seen in many parts of the body. Commonly seen in the oral cavity. Other places lichen planus occur are skin, genitals, ears, nails. Lichen planus occur when the immune system attacks the cells on the skin and mucous membranes. 
Pathophysiology of Lichen Planus
The immune system in your body is divided into acquired and the innate immunity. Innate immunity is the immunity we all are born with. This includes the skin and mucous membranes which are the natural barriers. This immunity is general and non-specific. If the pathogen is able to pass this barrier then the acquired immunity activates and try to destroy the pathogen. As the name implies acquired immunity is something you acquire throughout life. When you are exposed to diseases/pathogens (antigens) the body protects it and produce antibodies (response to the antigens) this will protect you from further attacks form the same pathogen. When you get vaccinated also your body produce antibodies and protect you form that disease. This is the acquired immunity. Acquired immunity is further divided into T-cell immunity and B-cell immunity. In autoimmune disease the acquired immune system attacks the normal cells identifying them as pathogens or faulty cells. There are many autoimmune disease and lichen planus is one of them. Lichen planus is a T-cell mediated autoimmune disease. T-cells triggers death in normal cells identifying these cells as faulty cells. This autoimmunity gives rise to the lesions.
Where Does Lichen Planus Occur?
Oral Cavity – lichen planus mainly occurs in the oral cavity. It includes the cheeks which is the common location in the oral cavity. Then it’s also seen in the tongue, gums, palate, and in the inner side of the lips. The lesions appear as
- Lacy, white, raised patches of tissues
- Red, swollen, tender patches of tissues
- Open sores
Skin – purplish lesion that are raise form the skin surface. These lichen planus lesions are itchy.
- Genitals (cutaneous lesions) – lesions occur in the female genital tract and it causes pain and discomfort with intercourse. These lichen planus lesions are red and eroded. Lesions can also appear in male genitals as well.
- Ears – this can lead to hearing loss.
- Scalp – this is quite rare however it can cause temporary or permanent hair loss.
- Nails – this can cause ridges, thinning or splitting of the nails. Even temporary or permanent nail loss can occur,
- Eyes – this is rare but however it can cause scarring and blindness.
- Esophagus – this is also rare. When it occurs it may cause narrowing of the esophagus or cause a tight ring like band on the esophagus. This will cause swallowing difficulties.
- Larynx – larynx lichen planus is also rare.
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