Seborrheic dermatitis and sarcoidosis

Dr César Bimbi presents a case in which sarcoidosis mimicked seborrheic dermatitis. Analysis of the skin lesions led to the diagnosis of sarcoidosis. The case illustrates why skin findings may sometimes reveal a systemic inflammatory disease.

Sarcoidosis mimicking seborrheic dermatitis: another case of “Sherlockian” dermatology

Cutaneous sarcoidosis is considered one of the great mimics in dermatology. Erythema nodosum is a typical non-specific skin lesion and is often associated with an acute presentation and generally a good prognosis. Papules, plaques, nodules, lupus pernio and infiltration of scars are more specific presentations and tend to be chronic, so treatment is often required.

Other differential diagnoses may include granulomatous rosacea, acne, benign adnexal tumours, psoriasis, lichen planus, nummular eczema, discoid lupus erythematosus, granuloma annulare, cutaneous T-cell lymphoma, secondary syphilis, Kaposi sarcoma, lupus pernio, scar-related furunculosis, cellulitis and inflammatory panniculitis.

Case report
A 28-year-old woman presented with a subtle, isolated, 5-mm infiltrated papule on the eyebrow that had been present for approximately six months. Examination of the skin revealed another asymptomatic, apple-jelly-coloured infiltrated papule on the left forearm.

A punch biopsy was performed. It showed confluent non-caseating granulomas composed of epithelioid cells with few lymphocytes. Tests for tuberculosis and fungal infection were negative.

At first, the patient denied respiratory symptoms. On further questioning, however, she recalled a persistent dry cough and exertional shortness of breath that had occurred over several months. Her personal, occupational and family histories were unremarkable. Peripheral lymph nodes were not enlarged. Cardiovascular, respiratory and neurological examinations were normal. Haematological and biochemical liver and kidney tests were normal, although urinary calcium was slightly elevated.

Summary
Even very small and apparently insignificant skin lesions may eventually reveal systemic disease, allowing earlier treatment and potentially improving the outlook.

This case describes a 28-year-old patient who consulted a doctor about a subtle, asymptomatic, 5-mm infiltrated papule on the left eyebrow that had appeared six months earlier. Biopsy of a similar lesion on the left forearm showed granulomatous features of sarcoidosis. Subsequent systemic assessment confirmed stage II pulmonary sarcoidosis and reticuloendothelial involvement, manifested by enlarged mediastinal lymph nodes.

The case highlights the skin as a possible mirror of internal multisystem disease and the importance of investigating even small and subtle lesions carefully and thoroughly.

Keywords: sarcoidosis; differential diagnosis; seborrheic dermatitis

Author: César Bimbi
Member of the Dermatology Board of the State Medical Council of Rio Grande do Sul, Brazil, and the Brazilian Society of Dermatology.
Corresponding author: Dr César Bimbi — cbimbi@terra.com.br

This page is educational and does not replace a medical examination or individual medical advice.