The aetiology is unknown. A number of organs can be involved, but the most common involvement is in the lungs, typically with enlargement of the lymph nodes in the hilar spaces of the lungs combined with parenchymal changes. Sometimes the liver and spleen are also enlarged, the musculoskeletal system, the organ of sight, the heart, the central nervous system may be involved, and some patients also develop skin lesions. This may be accompanied by general symptoms such as fatigue, weakness, weight loss and raised temperature. When the onset of the disease is sudden with fever, joint pain, erythema nodosum and enlarged hilar lymph nodes, this is referred to as Löfgren's syndrome.

In approximately 30 % of patients, the disease affects only the skin. The lesions take the form of nodular lesions or flat infiltrates.

There are several forms of 'cutaneous sarcoidosis':

• erythema nodosum-type form
• erythematous form with bluish-red infiltrates mainly on the face and hands
• a small nodular form, in which mainly the skin of the face is affected
• the vascular form, which develops more frequently in women; bluish lesions develop most often on the face and nose.

In about 80 % of patients, the lesions spontaneously disappear within two years of diagnosis. The skin lesions resolve without leaving scars. In the remaining cases, the disease takes a chronic form.

What is sarcoidosis, photo: panthermedia

The main drugs used to treat sarcoidosis are corticosteroids. General treatment is recommended when internal organs are involved and when skin lesions are extensive. In the early stages of the disease with only skin involvement or with hilar lesions, treatment is not necessary as the lesions may regress spontaneously - this occurs in approx. 60 % of cases. In these cases, only topical treatment in the form of ointment can be considered.