Skin lesions occur in 10 to 100 percent of cases, depending upon whether an internist or dermatologist is the observer. Cutaneous lesions are found two to eight times more often in women than in men. In four representative series composed of adults, cutaneous lesions, histologically specific for sarcoid, occurred in 16 to 36 percent. The prevalence of skin lesions in children is the same. In children, the disease occurs most commonly in the 8- to 15-year-old age group. Approximately 30 cases have been reported involving patients younger than 4 to 6 years old. The clinical features in the latter group are different from those seen in older children. The skin markers of sarcoid can be categorized as specific and nonspecific. The gross appearance of the specific eruption encompasses papules, nodules, plaques, subcutaneous tumors, and scaly erythematous and atrophic flat lesions. Although the lesions do not have a pathognomonic morphology, they do exhibit highly characteristic features that should strongly suggest the presence of the disease. Sarcoidosis can be diagnosed almost with certainty by histologic examination of specific lesions, thereby eliminating the need to biopsy lymph nodes, liver, muscle, or bronchial mucosa solely for diagnostic purposes.

Specific Lesions
The lesions of sarcoidosis are usually red or purple, but they can also have a reddish-brown or yellowish-brown hue. If the erythema is pressed out with a glass slide (diascopy), one can sometimes see tiny yellow-brown nodules produced by the granulomas; these nodules are similar to those seen in lupus vulgaris, the common form of cutaneous tuberculosis. Sarcoid lesions characteristically have a waxy translucent appearance and are almost never pruritic or painful.
Papules of sarcoidosis can arise anywhere on the body, affecting previously “normal” skin, but also occasionally occurring in surgical or posttraumatic scars and tattoos. Even scars many years old suddenly may become affected by the granulomatous reaction. Lesions are found most often around the eyes and in the nasolabial folds. These small elevated lesions are usually flat-topped, translucent, red or brown, and from 2 to 5 mm in diameter. Initially, papular lesions might be confused with flat warts or acne vulgaris, but on careful inspection, one can detect their characteristic translucence and color. The term maculopapular has been used to describe these small papules.
Papules can form a ring simulating granuloma annulare. However, the color and translucent quality of the lesions in sarcoid distinguish them from those of granuloma annulare; the borders of the latter are made up of opaque skin-colored papules. Annular lesions of sarcoid begin as papules that slowly expand peripherally and usually leave an atrophic and sometimes scaly center. In granuloma annulare, the center is neither scaly nor atrophic. Annular lesions also can be produced by plaques that undergo central atrophy. If the annular lesions have a yellow-brown color, it may be difficult to distinguish them clinically, but not histologically, from necrobiosis lipoidica. Annular lesions seem to be more common in American blacks than in other groups.
In one patient, the small papules of sarcoid mimicked lichen nitidus.
Nodules show a predilection for the extremities and trunk, but they have also been observed on the vermillion border of the lips, on the finger pulps and palms, and on the lateral margins of the foot. Translucency is not characteristic of nodules, but the red and purple colors are. The nodules arise in the deep dermis and subcutaneous layer, with calcification a rare development. Although deep nodules of sarcoidosis are often called Darier-Roussy sarcoid, the eponym is not correct. Darier-Roussy sarcoid is a term used by dermatologists to describe several nonspecific inflammatory disorders that involve the subcutaneous fat. Uncommonly, the papules and nodules may have a verrucous surface.
Plaques of sarcoidosis are almost always violaceous and translucent and may be widespread. Large telangiectatic vessels can be present on the surface, and some authors call these plaques angiolupoid lesions. However, when such extensive plaque formation arises on the ear lobes, nose, fingers, and toes, the term lupus pernio has been used. Sometimes, sarcoid mimics cutaneous T cell lymphoma (CTCL)—the plaques become tumor-like, simulating an early leonine facies, or they can be multiple, with superficially eroded surfaces and exhibiting the “pasted-on” appearance typical of CTCL patches and plaques.
Lupus pernio of the fingers and toes produces bulbous and sausage-shaped digits and is almost always associated with lytic lesions in the underlying phalanges. This is also a feature of sarcoidosis in infants and toddlers under 4 to 6 years of age. When the tip of the nose is involved by lupus pernio, the nasal bones may show osteoporosis and lytic lesions. The nasal mucosa may also be affected, producing purulent catarrh and obstructive symptoms. Bone involvement is present in 10 to 20 percent of patients. Although the bones most frequently involved are those of the hands and feet, occasionally the long bones, vertebrae, ribs, skull and facial bones, show identical lytic lesions. However, radiographic examination of the hands and feet of patients with sarcoid is worthwhile only if they have lupus pernio or chronic skin lesions elsewhere. Bone involvement may also portend a poorer prognosis in adults. The mortality rate of such patients was 21 percent in James' series, four times greater than the overall rate. 15 However, bony lesions, which are also a characteristic feature of sarcoid in children younger than 4 to 6 years of age, do not appear to be associated with a poor prognosis.
Nail deformities can arise when lupus pernio develops close to the posterior nail fold. Often, the underlying bone will have lytic lesions. The nail plate may become thickened with an irregular surface. Sometimes there is distal crumbling of the nail plate.
Sarcoidal lesions can also take the form of red, violaceous, yellowish-brown, or reddish-brown scaly macules or patches. The scale varies from thin and scant to heavy and thick. These types of lesions tend to develop cutaneous atrophy. When the scalp is affected, alopecia frequently results, mimicking lupus erythematosus and pseudopelade. When the face is affected, the “discoid” lesions of cutaneous lupus erythematosus are simulated. On the trunk and extremities the picture of psoriasis or CTCL can be simulated, and on the palms, the appearance of secondary syphilis is mimicked. Psoriasiform lesions are considered to be characteristic of sarcoid in American blacks.
Well-demarcated, generalized, scaly, reddish-brown patches are rare manifestations that appear and remit intermittently over the course of years. In the acute phase, small superficial pustules arise within the patches. In the chronic phase, pustules are absent. The palms may be involved. When this reddish-brown scaling eruption covers extensive portions of the legs, buttocks, and trunk, the term “erythrodermic” sarcoidosis has been applied. In three persons, generalized skin involvement developed, simulating exfoliative dermatitis. Extensive involvement also may simulate poikiloderma vasculare atrophicans.
Ulceration may be a complication of lupus pernio on the nose and ears. Rarely, cutaneous plaques and deep cutaneous and subcutaneous nodules may ulcerate. Other uncommon manifestations include generalized perifollicular papules and pustules as the specific cutaneous markers of sarcoidosis. An ichthyosis-like picture has also been produced by the cutaneous granulomas. Only the ichthyotic areas show the histopathology of sarcoidosis.
Hypopigmentation is an uncommon manifestation. It may develop over papules and nodules or it may exist as patches that feel normal or slightly indurated. In the latter instance, papules and nodules usually arise later within or adjacent to the hypopigmented macules. Biopsies have shown sarcoid granulomas in the macules, papules, and nodules. All reported cases have been black patients. The hypopigmentation appears to be related to decreased melanization of the overlying epidermal cells. The melanocyte count is normal, and there is no evidence of postinflammatory hypopigmentation.
Occasionally, the oral mucosa and palpebral conjunctivae are involved with granulomas. Violaceous plaques can develop on the hard palate and gingivae.

Nonspecific Lesions
Erythema nodosum is a nonspecific sign of sarcoidosis that occurs most frequently in women 20 to 35 years old. Erythema nodosum with hilar adenopathy, arthralgia, fever, and chills is frequently the initial manifestation of sarcoidosis. When erythema nodosum occurs in sarcoid, the latter usually behaves as a benign self-limited disorder. As a general rule, progressive disease is associated with the presence of specific lesions, and not with erythema nodosum. However, exceptions do occur. The author has recorded five patients in whom sarcoidosis began with erythema nodosum and progressive sarcoidosis involving lung and liver developed a few months later. The prospective study of Veien et al. reported similar observations. 16 Several large series from different countries, compiled from 1960 to 1974, indicate that sarcoidosis is the cause of erythema nodosum in 37 percent of the cases (range, 11 to 74 percent). 17 The prevalence of erythema nodosum in sarcoidosis ranges from 4 to 35 percent (average, 17 percent). In the author's experience, sarcoid has accounted for 16 percent of the cases of erythema nodosum and erythema nodosum has occurred in 10 percent of patients with sarcoidosis.
Sarcoid in children 8 to 15 years of age is indistinguishable from that seen in adults. However, sarcoid in children younger than 4 to 6 years of age behaves differently. 14 Sarcoid can appear in infants as early as 4 months. These infants and toddlers have more joint involvement and rashes, less pulmonary disease, and eye problems only slightly more frequently than occurs in older children. The skin rashes have been described as eczematous and papular. Erythema nodosum may occur as multiple lesions and involve the soles, as well as more typical locations. The joints show a symmetric boggy synovitis without much pain or limitation of motion. Generally, the radiologic findings are negative. Although joint involvement usually does not lead to disability or contractures, sometimes they do occur. The fingers may be affected with a fusiform swelling, in which case one often finds lytic lesions and osteoporosis in the underlying bones, as in adults. In these children, multisystem involvement develops over periods of weeks to more than a year.
Eye involvement takes the form of phlyctenular keratoconjunctivitis, uveitis, miliary retinitis, and optic retinitis. Marked visual impairment has occurred in a few children.