Dermatology - Sarcoidosis

Dermatology - Sarcoidosis 
A systemic granulomatous illness with a range of cutaneous manifestations, sarcoidosis primarily affects the lungs (bilateral lymphadenopathy, pulmonary infiltration) and has an unknown etiology. Onset often occurs before 40.

Fever, exhaustion, weight loss, and arrhythmia are examples of constitutional symptoms. Lesions might appear days after other symptoms (acute erythema nodosum) or months later (asymptomatic sarcoidal papules, plaques on the skin, or pulmonary infiltration seen on regular chest radiography).

The skin-colored papules around the mouth are the first lesions to appear. Afterwards, the trunk, buttocks, and extremities are the primary sites for brownish or purple infiltrating plaques that can be annular, polycyclic, or serpiginous. There may be central clearing accompanied by mild atrophy. Firm purple or brown nodules on the face, torso, or extremities—especially the hands—may occasionally appear.
Diffuse, violaceous, soft, doughy infiltrations on the nose, cheekbones, or earlobes are indicative of lupus pernio.
Because of osteitis cystica, individual digits may enlarge. Old scars are often infiltrated by sarcoidosis, resulting in translucent purple-red or yellowish papules or nodules. All cutaneous lesions of sarcoidosis exhibit a semitranslucent yellowish brown tint known as "apple jelly" when blanched on a glass slide. Sarcoidosis can result in scarring alopecia on the scalp.

Skin or lymph node lesional biopsies are used to make the diagnosis.

When there is a CNS involvement, cardiac arrhythmia, active lung disease, active ocular disease, or hypercalcemia, systemic glucocorticoids are used. Intralesional triamcinolone (3 mg/mL) is useful for minor lesions in cutaneous sarcoidosis, but systemic glucocorticoids are administered for extensive or deformity-causing involvement. When intralesional triamcinolone is ineffective for widespread or disfiguring lesions, low-dose methotrexate or 100 mg of hydroxychloroquine twice day may be administered; however, these treatments are not always successful.
Only diseases that have the potential to be fatal are treated with cyclophosphamide.