Sarcoidosis, a multisystemic disease of unknown etiology, may involve virtually any organ in the body, including the lungs, lymph nodes, liver, spleen, eyes, etc. [1] [2] [3]. In approximately 25-35% of patients, it can cause skin-related symptoms, in which case the term cutaneous sarcoidosis is used [3] [4] [5]. Furthermore, reports show that cutaneous signs of the disease are the only manifestation in 3-5% of patients [4] [5]. Numerous skin lesions have been reported in the literature, but the two most common and most important are [3] [6]:

• Erythema nodosum - Despite its nonspecific nature (may be seen in drug-induced, infection-related, or inflammation-induced hypersensitivity reactions as well), the sudden appearance of erythematous nodules in the subcutaneous tissues of the anterior tibia is a rather common cutaneous sign of sarcoidosis [6]. The nodules are very tender on palpation and are often accompanied by fever, joint pain, and malaise [6].
• Lupus pernio - The presence of purple-to-red indurated papules, plaques, or nodules on the face (the alar rim of the nose and surrounding area) is a more specific feature of cutaneous sarcoidosis, and is more frequently seen in women [3] [6]. Telangiectasias can also develop together with lupus pernio [5].

In addition to erythema nodosum and lupus pernio, single or multiple papules or plaques of different sizes and colors (red, brown, hypopigmented or even translucent) developing on the face and the extremities, either as isolated lesions or in a confluent pattern are other notable manifestations of this disease [2] [6]. In some cases, the term is used to denote the appearance of the lesion in a preexisting scar (scar sarcoidosis) [6].

As cutaneous sarcoidosis possesses numerous types of lesions, it might be difficult to establish a diagnosis solely on clinical criteria. Nevertheless, the initial suspicion towards this inflammatory disease can only be raised after a thorough physical examination and a meticulously obtained patient history [4] [6]. This condition often (but not always) precedes involvement of other organs and systemic symptoms, thus the detection of associated lesions is perhaps the only tool in making a presumptive diagnosis. Given the systemic nature of the disease, a thorough laboratory workup should be performed, comprising liver and kidney function tests, serum inflammatory markers, and angiotensin-converting enzyme (ACE) [1] [6]. In addition, chest radiography, pulmonary function tests, electrocardiography (ECG), and a complete ophthalmologic exam are recommended in the workup [6]. To confirm the diagnosis of cutaneous sarcoidosis, however, biopsy of the skin with subsequent histopathological examination is the gold standard [1]. A punch biopsy allows a satisfying amount of tissue to be obtained, and the presence of non-caseating granulomas is virtually a pathognomonic finding of sarcoidosis [1] [5].

Treatment for cutaneous sarcoidosis aims to reduce inflammation and manage symptoms:

• Topical Corticosteroids: Creams or ointments applied directly to the skin to reduce inflammation.
• Oral Corticosteroids: Used for more severe cases to control systemic inflammation.
• Immunosuppressive Agents: Medications like methotrexate or hydroxychloroquine may be used for chronic cases.
• Laser Therapy: In some cases, laser treatment can help reduce the appearance of lesions.

The prognosis for cutaneous sarcoidosis varies. Some patients experience spontaneous resolution of skin lesions, while others may have chronic or recurrent symptoms. The overall prognosis is generally favorable, especially with appropriate treatment. However, the presence of systemic sarcoidosis can affect the overall outcome.

The exact cause of sarcoidosis, including its cutaneous form, remains unknown. It is believed to result from an abnormal immune response, possibly triggered by environmental factors, infections, or genetic predisposition. The formation of granulomas is a hallmark of the disease, but why they form is not fully understood.

Sarcoidosis is a relatively rare condition, with cutaneous involvement occurring in about 25% of cases. It can affect individuals of any age but is most commonly diagnosed in adults between 20 and 40 years old. The disease is more prevalent in certain populations, including African Americans and people of Scandinavian descent.

The pathophysiology of cutaneous sarcoidosis involves the formation of granulomas in the skin. These granulomas are composed of clusters of immune cells, primarily macrophages and T-lymphocytes. The exact mechanism that triggers granuloma formation is not fully understood, but it is thought to involve an exaggerated immune response to an unknown antigen.

There are no specific measures to prevent cutaneous sarcoidosis, as the exact cause is unknown. However, managing overall health and avoiding known triggers, such as certain environmental exposures, may help reduce the risk of flare-ups in individuals with a known diagnosis.

Cutaneous sarcoidosis is a manifestation of sarcoidosis that affects the skin, presenting with various types of lesions. Diagnosis involves clinical evaluation and biopsy, while treatment focuses on reducing inflammation and managing symptoms. The prognosis is generally favorable, though the disease can be chronic. The exact cause remains unknown, and prevention strategies are limited.

If you have been diagnosed with cutaneous sarcoidosis, it's important to follow your healthcare provider's treatment plan and attend regular check-ups. While the condition can be chronic, many patients manage their symptoms effectively with treatment. If you notice new or worsening skin lesions, contact your healthcare provider for further evaluation.

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2. Dybiec E, Pietrzak A, Bartosińska J, Kieszko R, Kanitakis J. Ultrasound findings in cutaneous sarcoidosis. Postepy Dermatol Alergol. 2015;32(1):51-55.
3. Haddad N, de Oliveira J, Nasser K da R, Corbett AMF, Tebet ACF, Reis MLJ. Musculoskeletal and cutaneous sarcoidosis: exuberant case report. An Bras Dermatol. 2014;89(4):660-662.
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6. Katta R. Cutaneous sarcoidosis: a dermatologic masquerader. Am Fam Physician. 2002;65(8):1581-1584.