Cutaneous manifestations of sarcoidosis.

Sir,

We read with interest the case report titled ‘Cutaneous sarcoidosis — A great masquerader: A report of three interesting cases’ by Reddy et al.[1] The authors have aptly stressed on the fact that cutaneous sarcoidosis can present with various morphological skin manifestations, and can also mimic several other common dermatological disorders. The diagnosis of sarcoidosis requires a compatible clinical picture, histological demonstration of non-caseating granulomas, and exclusion of other diseases.

The authors have described a 28-year-old female with multiple erythematous papular lesions over her face and extremities (Case 1) and a 15-year-old boy who presented with multiple skin-colored to reddish-brown, translucent papules on the cheeks, nose, upper lip, chin, and forehead (Case 3).[1] They considered acne, histoid leprosy, and trichoepitheliomas as the possible clinical differential diagnoses.[1] We think it is important to add acne agminata and granulomatous perioral dermatitis to this list as well.

Acne agminata or lupus miliaris disseminatus faciei (LMDF) resembles the papular form of cutaneous sarcoidosis, not only clinically, but also histologically.[2] It presents as multiple monomorphic symmetrical reddish brown papules on the chin, forehead, cheeks, and eyelids, in young adults and adolescents of either gender, which may infrequently heal with scarring.[2] The acronym facial idiopathic granulomas with regressive evolution (FIGURE) has recently been proposed for this disease.[3] In acne agminata the characteristic histopathological features of fully developed lesions include a sarcoidal granuloma (first stage), sometimes accompanied by abscess formation (second stage), or caseation necrosis (third stage).[4] These granulomas, which are thought to arise as a foreign body reaction to keratin from disrupted hair follicles, are histologically indistinguishable from those of sarcoidosis.[4] Thus, a biopsy specimen should be interpreted with caution if taken from the skin of the face.

The diascopy of the lesions in sarcoidosis, not described by the authors in any of their cases, reveals an apple jelly, nodule-like appearance indicating their granulomatous etiology.[5] On applying pressure with a glass slide, the erythematous color of the papules is mitigated and the yellow brown color can be more easily appreciated. This change is not specific to sarcoidosis and can be observed in other skin conditions with granulomatous inflammation, including lupus vulgaris, granuloma annulare, and acne agminata.[35]

Granulomatous perioral dermatitis, also known as sarcoid-like granulomatous dermatitis is another papular eruption, with lesions confined to the face, documented more commonly in Afro-Caribbean children. The histology is variable, ranging from non-specific inflammation with hyperkeratosis, or more commonly granulomatous with a few inflammatory cells.[2]