Lichen planus is a skin condition that, despite its name, is not caused by fungi, nor is it contagious. Instead, this condition appears to be a systemic response to stress on the body. Although lichen planus can cause some discomfort, it rarely causes any serious medical problems, although an infection of the mouth does predispose patients to the development of oral cancer.
Cause
Lichen planus is not caused by any infectious or contagious agent, the Mayo Clinic notes. In some cases, an allergic or immunological reaction to medications, allergens, or other substances appears to trigger the condition, which suggests that lichen planus is caused by abnormal behavior on the part of the immune system. Some infections, such as hepatitis C can also lead to an outbreak. In many cases, however, the trigger for lichen planus cannot be identified.
Symptoms of Skin Lichen Planus
Lichen planus leads to the appearance of reddish-purple patches on the skin, the American Academy of Dermatology explains. These bumps, which are flat on top, can be very itchy. In some cases, the bumps may have a white and lacy pattern, which is also known as Wickham's striae. This skin condition can occur anywhere on the body, though the inside of the wrists and ankles is the most common location. The lower back, genitals, neck, legs, scalp and nails may also be affected. When lichen planus affects the legs, the bumps are typically darker, and can form thick patches on the shins, which is also known as hypertrophic lichen planus. One rare form of the disease, known as bulbous lichen planus, can form blisters.
Oral Lichen Planus
Lichen planus can also affect the oral cavity, Medline Plus notes. When lichen planus affects the mouth, it most commonly causes the appearance of small blue-white spots, which may be tender or mildly painful. They are typically found on the sides of the tongue or the insides of the cheek, though in rare cases they can appear on the gums. The skin lesions usually occur in lines and form a small lacy network, which can cause some mild enlargement of the affected area. Oral lichen planus is associated with an increased risk of developing oral cancer.
Diagnosis
The skin lesions caused by lichen planus are distinctive, so in many cases, the appearance of raised flat-topped bumps on the skin is enough to make a dermatologist suspect lichen planus. These symptoms, combined with the patient's medical history are a major component of the diagnosis. Patients may also receive a procedure called a punch biopsy, the Mayo Clinic notes, in order to definitively diagnose lichen planus. This procedure involves the use of a small tool that removes a circular piece of tissue about six millimeters below the surface of the skin. This sample can then be examined underneath a microscope.
Treatment
In general, lichen planus will go away on its own without any treatment. However, because these skin lesions can become itchy, patients may undergo some treatment to relieve the itching. Patients may take antihistamines, or apply ointments with corticosteroids, such as hydrocortisone, to reduce inflammation. Ointments that have other kinds of immune-altering agents, such as imiqumod and tacrolimus can also be used. In severe cases, patients may take oral corticosteroids, or expose the affected areas to ultraviolet light.
