INTRODUCTION
Sarcoidosis is a systemic disease that is identified by the key feature of non-caseating granulomatous inflammation in the affected organ.11 The diagnostic criteria for sarcoidosis include a clinical and radiologic presentation of sarcoidosis, evidence of non-caseating granulomas, and exclusion of other causes of disease.11 While the etiology of sarcoidosis is unknown, it is hypothesized that there may be a genetic predisposition or environmental factors that influence the disease progression.1,10 The non-caseating granulomas develop due to the overstimulation of Th1 cells to secrete interferon gamma (IFN-γ), which activates macrophages. The activated macrophages then promote the secretion of cytokines such as tumor necrosis factor alpha (TNF-α) which leads to the production of the epithelioid histiocytes and the formation of the multinucleated giant cells that make up the composition of the non-caseating granuloma.
Sarcoidosis can affect patients of all ages and racial backgrounds, but it predominantly presents in African American females.1,4 The pulmonary system is the most affected organ, and the skin is the second most common. Cutaneous sarcoidosis can be found on any skin surface including mucosal layers, and it has a higher propensity to develop in sites of previous skin disruption such as in scarring from injury or tattoos.4 Clinical presentations of cutaneous sarcoidosis include lupus pernio, papular sarcoidosis, nodular sarcoidosis, plaque sarcoidosis, scar sarcoidosis, and erythema nodosum.7 Given its high prevalence in African American women, it is essential to be familiar with the various cutaneous presentations of sarcoidosis for early detection and treatment, especially in skin of color.
Sarcoidosis can affect patients of all ages and racial backgrounds, but it predominantly presents in African American females.1,4 The pulmonary system is the most affected organ, and the skin is the second most common. Cutaneous sarcoidosis can be found on any skin surface including mucosal layers, and it has a higher propensity to develop in sites of previous skin disruption such as in scarring from injury or tattoos.4 Clinical presentations of cutaneous sarcoidosis include lupus pernio, papular sarcoidosis, nodular sarcoidosis, plaque sarcoidosis, scar sarcoidosis, and erythema nodosum.7 Given its high prevalence in African American women, it is essential to be familiar with the various cutaneous presentations of sarcoidosis for early detection and treatment, especially in skin of color.
Types of Cutaneous Sarcoidosis
Diagnosing sarcoidosis can be challenging because of the wide array of presentations associated with the disease. Comprehensive evaluations for sarcoidosis must be done early and include combined evaluations of a patient's clinical exam, blood work, radiologic imaging, and histologic features. The diagnosis of sarcoidosis is confirmed with biopsy indicating the presence of non-caseating granulomas. The absence of non-caseating granulomas in the skin does not rule out the diagnosis but is required in all of the specific skin findings described below.6
Specific Skin Findings
Papular Sarcoidosis
Papular sarcoidosis is the most common skin manifestation of sarcoidosis.6 The papules are elevated skin lesions typically seen on the face, but they can be seen in any location on the body (Figure 1). Papular sarcoidosis is <1 mm in size and varies in color from reddish-brown to violaceous.5 The papules are firm to palpation and have an “apple jelly” appearance when pressure is applied.6
Differential diagnoses: Rosacea, Sebaceous hyperplasia, Xanthoma.
Differential diagnoses: Rosacea, Sebaceous hyperplasia, Xanthoma.
