Cutaneous sarcoidosis

Cutaneous sarcoidosis is a manifestation of sarcoidosis, a systemic granulomatous disease that primarily affects the lungs but can also involve multiple other organs, including the skin. Cutaneous sarcoidosis refers specifically to the involvement of the skin in this disease process.

Etiology and Pathogenesis

The exact cause of sarcoidosis is unknown, but it is thought to involve a combination of genetic and environmental factors. The disease is characterized by the formation of immune system cells into clumps known as granulomas, which can cause inflammation and damage in the affected tissues. In cutaneous sarcoidosis, these granulomas form in the skin.

Clinical Presentation

Cutaneous sarcoidosis can present in several forms, ranging from maculopapular eruptions to plaques and subcutaneous nodules. The lesions may appear as red-brown or purple plaques, often located on the face, the back of the hands, the arms, and the legs. The lupus pernio form is notable for its chronic, persistent, and disfiguring lesions on the face. Another form, erythema nodosum, is characterized by tender red nodules, usually found on the lower legs. It is often associated with acute sarcoidosis and may resolve spontaneously.

Diagnosis

Diagnosis of cutaneous sarcoidosis involves a combination of clinical evaluation, histopathological examination, and exclusion of other diseases with similar presentations. A skin biopsy is crucial for confirming the diagnosis, showing non-caseating granulomas without evidence of organisms. Additional tests might include chest X-rays or CT scans to check for pulmonary involvement, as well as blood tests to assess organ function and calcium levels.

Treatment

Treatment of cutaneous sarcoidosis varies depending on the severity and extent of the disease. Mild skin lesions may not require treatment and can resolve spontaneously. More severe cases might be treated with topical or intralesional corticosteroids, antimalarial drugs like hydroxychloroquine, or systemic medications such as methotrexate or TNF inhibitors. The choice of treatment depends on the patient's overall health, symptoms, and the presence of sarcoidosis in other organs.

Prognosis

The prognosis for cutaneous sarcoidosis is generally good, though the disease can be chronic and may recur. Skin lesions may resolve on their own or with treatment, but in some cases, they can persist or leave scars.

Epidemiology

Cutaneous sarcoidosis occurs worldwide and can affect individuals of any age, but it is more common in adults between the ages of 20 and 40. It tends to be more prevalent in women than in men and is more commonly seen in people of African descent.

See Also

• Granuloma
• Autoimmune disease
• Immunology