Cutaneous
sarcoidosis is not an uncommon disorder, and the skin can be the sole manifestation in about 10% of patients. However, when the involved anatomical area of the cutaneous
sarcoidosis is the scalp and it presents as a
scarring alopecia, there is an increased risk of a systemic disease (1,2). A 79-year-old Caucasian male patient presented to our Institute with annular and painless plaques of the scalp, with variable diameter, showing a reddish and yellowish color (Figure 1, a). Furthermore, a scleroderma-like
atrophy of the skin with an exposure of the underlying vasculature was present (Figure 1, b). The patient reported that these lesions began to appear 2 years ago, with a worsening in the last 6 months. He also reported a
chronic cough and
dyspnea. According to the patient's medical history, he was treated for
tinea capitis with
radiotherapy of the scalp at the age of 7, with temporary
hair-loss and subsequent total re-growth. Additionally, during the last 7 years he was diagnosed with mental depression and treated accordingly. The histology revealed typical epithelioid cell
granulomas without central
necrosis in association with a sparse lymphocytic infiltrate. Elastosis with ectatic vessels,
sclerosis, and
edema was also present in the upper dermis (Figure 1, c, d) A diagnosis of cutaneous
sarcoidosis of the scalp was established. Laboratory investigations, including
hepatitis B and C viral serology, anti-nuclear
antibodies,
antibodies to
extractable nuclear antigen,
cardiolipin, beta2
glycoprotein immunoglobulin G antibodies, and lymphoid subsets were all in normal ranges, whereas the
angiotensin converting enzyme level was 124 (range: 65-114) IU/L. The chest radiography showed diffuse interstitial nodulations with bilateral and right para-tracheal
lymphadenopathies, and the histology revealed
pulmonary sarcoidosis (Figure 2). As of this writing, the patient is undergoing steroidal treatment with periodical clinical and instrumental follow-up, with poor response from the cutaneous lesions but an improvement of the pulmonary symptoms. Scalp
sarcoidosis is a not frequent finding (1). Most of the reported cases are Afro-American female patients. Although the main clinico-pathological differential diagnosis is atypical
necrobiosis lipoidica, this entity differs from cutaneous
sarcoidosis by an absence of scalp
scarring alopecia and by the fact that the annular lesions are often limited to the face, without involving the scalp (1-4). Additionally, histologically atypical
necrobiosis lipoidica does not reach the typical features of a sarcoid
granuloma. Other potential misdiagnoses are
morphea,
discoid lupus erythematosus, and lichen plano-pilaris (1-4).
Sarcoidosis is most likely driven by a putative
antigen in genetically susceptible individuals (5). Although radiation exposure is one of the possible causes of
sarcoidosis, the
radiotherapy used for the
fungal infection did not have any role in the onset of the disease in our patient, as confirmed by the normal total regrowth of the hairs and the long-time interval. Regarding the
therapy (mainly
steroids,
azathioprine, and
hydroxychloroquine), if compared to other anatomical sites, the grade of
atrophy in the scalp is always too high to allow an objective clinical response, as observed in our patient. This case emphasizes that in cutaneous annular
sarcoidosis of the scalp, an underlying systemic
sarcoidosis is often present.