Sarcoidosis is an example of a systemic disease in which cellular granulomatous infiltrates produce dermal skin lesions.

Sarcoidosis is a chronic multisystemic disease of unknown origin. Most often, it presents with bilateral hilar adenopathy, pulmonary infiltration, eye lesions, and arthralgias; less commonly, there is involvement of the spleen and salivary and lacrimal glands, as well as gastrointestinal and cardiac manifestations.

Sarcoidosis is seen most commonly in young adults, particularly in blacks in the United States and South Africa. It is also more common in Scandinavians.

Of patients with sarcoidosis, 20% to 35% have cutaneous involvement. It usually accompanies systemic symptoms but may be the only site of involvement.

African Americans have a greater risk of developing more serious problems such as cystic bone lesions, chronic uveitis, and chronic progressive disease.

Skin lesions are generally asymptomatic; however, they are often of great cosmetic concern because they occur commonly on the face.

Specific lesions of cutaneous sarcoid include the following:

• Dermal papules, nodules, or plaques that are brown or violaceous (Fig. 34.39).

• Lesions may be annular, serpiginous, or atrophic.

• Lesions may also appear on dorsa of hands, fingers, toes, and forehead.

• Lupus pernio, a distinct variant, consists of reddish purple plaques around and on the nose, ears, lips, and face (Fig. 34.40). Lupus pernio also occurs with a higher frequency in African Americans and Puerto Ricans.

• Subcutaneous nodules (Darier-Roussy nodules). These usually nontender, firm, oval, flesh-colored, or violaceous 0.5- to 2-cm nodules are found on the extremities or trunk.

• Löfgren syndrome (erythema nodosum and arthritis) is a clinical variant of sarcoidosis.

  Nonspecific cutaneous lesions associated with sarcoid include the following:

• Erythema nodosum (see above in this chapter), which more commonly affects Scandinavian populations. When associated with sarcoidosis, EN generally resolves spontaneously and suggests a better prognosis.

• Acquired ichthyosis may also be noted.

“Apple jelly” nodules are seen on blanching lesions with a glass slide (diascopy). These nodules represent the gross appearance of granulomas.

Skin biopsy demonstrates noncaseating granulomas (sarcoidal granulomas).

A chest radiograph may demonstrate bilateral hilar adenopathy and other characteristic changes.

Abnormal laboratory evaluations may include the following:

• Elevated angiotensin-converting enzyme levels.

• Hypergammaglobulinemia.

• Hypercalcemia.

Lesions tend to be located periorificially (e.g., around the eyelids, nasal ala, tip of nose, earlobes, and lips).

Lesions may occur in old scars anywhere on the body (Fig. 34.41). Scars from previous traumas, surgery, venipuncture, or tattoos may become infiltrated and may be red or purple.

Scalp lesions may produce scarring alopecia.

Ichthyosiform and lesions of EN tend to occur on the pretibial area.