Dermatological sarcoidosis

Cutaneous involvement of sarcoidosis is thought to occur in around 24% of cases (1)

• skin lesions usually appear at the onset of systemic illness
• due to the inconsistent nature of these lesions, diagnosis may be overlooked or misinterpreted even by the most experinced clinicians (2)
• scars, pits and pale depigmented areas may occur in American Afro-Caribbean patients after skin lesions (1)

Eruptions can be:

• specific - where typical granulomatous infiltrates are seen in sample tissue, examples include maculopapular and nodular eruptions (most common), infiltrated scars, subcutaneous lesions, and lupus pernio (LP)
• nonspecific - most common is erythema nodosum (EN), other non specific manifestations are uncommon and include calcifications, erythema multiforme, prurigo, nail clubbing, and Sweet syndrome (an acute febrile neutrophilic dermatosis) (2)

Features include:

• erythema nodosum (EN)
  • sarcoid-associated EN are seen in around 25% of cases
  • common in white Europeans and rare in Afro-Caribbean and Japanese people (3)
  • it is often accompanied by arthritis, edema (particularly on the ankles), and low-grade fevers
  • spontaneous resolution of the lesions (without complications) can be seen after 1 to 3 weeks, reocurence can be seen in some cases
  • Löfgren syndrome is an acute presentation of systemic sarcoidosis where there is a combination of EN with bilateral hilar lymphadenopathy, and polyarthralgias, or arthritis
    • common in young women of Scandinavian, Irish, or Puerto Rican ancestry
    • this form of sarcoidosis carries an excellent prognosis with a more rapid spontaneous rsolution of the disease (2)
  • the incidence of erythema nodosum and arthralgia in association with sarcoidosis is associated with HLA-B8
  • usually lesions of EN are not sampled for biopsy except in cases where clinical diagnosis is unclear e.g - when eruptions of subcutaneous sarcoidosis on the legs may be indistinguishable from EN (2)

Other skin lesions include plaques, nodular infiltrates, lupus pernio, subcutaneous nodules, annular lesions, and scar infiltration:

• these features are more common in Afro-Caribbeans than caucasians
• also they are associated with more florid cases and a worse prognosis
• occasionally lesions similar to necrobiosis lipoidica diabeticorum may occur

Reference:

• (1) Lodha S et al. Sarcoidosis of the skin: a review for the pulmonologist. Chest. 2009;136(2):583-96.
• (2) Iannuzzi MC, Rybicki BA, Teirstein AS. Sarcoidosis. N Engl J Med. 2007;357(21):2153-65
• (3) Dempsey OJ et al. Sarcoidosis. BMJ. 2009 Aug 28;339:b3206