Diagnosis: Scar sarcoidosis
Sarcoidosis is a systemic granulomatous disease that may affect any organ system, and therefore may present with various clinical manifestations.1 Sarcoidosis can be an incidental finding on chest x-ray or be discovered in patients that present with respiratory or constitutional symptoms.2
Cutaneous sarcoidosis occurs in up to one third of patients with systemic sarcoidosis.2 The classic skin lesions are “erythema nodosum”—an acute, nodular, erythematous eruption that usually is limited to the shins, and “lupus pernio”—red-to-purple or violaceous indurated nodules affecting the nose, cheeks, ears, and lips. There are other uncommon skin presentations of sarcoidosis ranging from scattered papules and annular lesions to erythrodermic skin manifestations.3
In scar sarcoidosis, there is spontaneous development of livid or reddish-brown plaques on scars that were previously atrophic for the most part. Scar sarcoidosis may be caused by:4-6
- venipuncture
- tuberculin skin tests
- herpes zoster
- tattoos
- cosmetic fillers such as hyaluronic acid injection.
Infection and other factors may be at work
Although the precise cause of sarcoidosis remains unknown, various infectious, noninfectious, environmental, and genetic factors may be at work. Researchers have theorized that immune dysregulation may be involved. Contact with a persistent antigen that is poorly cleared by the immune system may lead to T lymphocytes and mononuclear phagocytes accumulating in the granulomas of sarcoidosis.7 Researchers have proposed that inoculation of foreign matter from minor trauma may be one type of pathogenic mechanism in cutaneous sarcoid.8