Lichen ruber planus

Definition

Lichen ruber planus, also known as nodular lichen, is a non-infectious chronic inflammatory disease of the skin and mucous membranes that occurs in relapses. Itchy nodules are formed, which occur particularly frequently on the bend of the wrists and back of the knees, on the upper body and on the soles of the feet. But other parts of the body such as the fingernails and mucous membranes in the area of the mouth or genitals can also be affected.

Furthermore, whitish stripes of the mucous membranes, so-called Wickham’s stripes, are typical. The frequency peak of the disease is between the ages of 30 and 60, with women being affected more often than men. Lichen ruber planus is the most common idiopathic (unknown cause) skin disease worldwide.

Causes of lichen ruber planus

The causes for the development of lichen ruber planus are not yet fully understood, but presumably it is a virus-related autoimmune reaction or contact allergic reaction. Normally, the human immune system fights pathogens and substances that are perceived as “foreign”. In the case of nodular lichen, there is much to suggest that the defense cells mistakenly attack and destroy the body’s own keratinocytes (horny cells) of the skin by certain triggers.

It is assumed that certain genetic variations in the genome increase the risk of developing lichen ruber planus. In addition to a genetic component, viral infections are also suspected to be the cause of the disease. In particular, the hepatitis C and hepatitis B viruses appear to promote an outbreak of nodular lichen and patients suffering from such chronic infections are often affected by corresponding skin lesions.

Allergies are also associated with nodular lichen and can sometimes trigger it: often, the later stages of the disease form in places that are already inflamed by a chronic allergic reaction. An outbreak of the disease can also be triggered by external stimuli such as scratching, rubbing or pressure on the skin (Koebner phenomenon). In addition, a connection with the intake of certain medications, such as beta-blockers, painkillers or antibiotics, is being discussed. However, these factors are not certain.