Key messages from a rare case of annular sarcoidosis of scalp.

Sarcoidosis, a multisystem disease of obscure etiology, is characterized by the formation of noncaseating epithelioid cell granulomas in several organs or tissues. The diagnosis of sarcoidosis requires a compatible clinical picture, histologic demonstration of noncaseating granulomas, and exclusion of other diseases capable of producing similar histology or clinical features. The lung is the most commonly affected organ, but the skin is frequently involved. Sarcoidosis occurs worldwide and affects all ages and races with female predominance. Scalp involvement is decidedly rare among the myriad cutaneous manifestations of sarcoidosis. Alopecia is common in sarcoidosis and is generally scarring in nature. Annular sarcoidosis is a rare morphology and annular sarcoid of scalp is seldom reported. Herein we present a case of annular scalp sarcoid with systemic involvement and without alopecia.

INTRODUCTION

Sarcoidosis, a multisystem disease of obscure etiology, is characterized by the formation of noncaseating epithelioid cell granulomas. Symptoms of sarcoidosis are nonspecific and depends on the organ involved. The main organs affected are the lungs, lymph nodes, and eyes in the order of frequency.[1] Cutaneous involvement is polymorphic and is seen in 20%–35% patients with systemic sarcoidosis.[2] Scalp involvement is decidedly rare among the myriad cutaneous manifestations of sarcoidosis.[3] Even there, the annular sarcoidosis of scalp with scarring alopecia has been reported only once before.[4] Herein we present a case of annular scalp sarcoid with systemic involvement and without alopecia.

CASE REPORT

A 44-year-old married male presented with complaints of multiple asymptomatic red patches over his scalp since seven months. He was apparently asymptomatic seven months back when his barber noticed a red patch over the vertex area of scalp, which gradually increased in size, shape, and number to involve other areas of scalp for which he consulted various private practitioners who prescribed him topical steroids but there was no improvement for which he came to our institution. The patient did not report any hair loss. He was a known case of pulmonary sarcoidosis since one year and was taking corticosteroid in the form of rotacaps for the same.

On examination, multiple, well-defined, annular plaques with raised erythematous to violaceous infiltrated margin were present over occipital, temporal, frontal areas, and vertex of clean shaven scalp. Hair follicles were preserved in the areas of central clearing without any evidence of scarring [Figure 1]. Rest of the mucocutaneous examination was unremarkable. Differential diagnosis of annular lichen planus, discoid lupus erythematosus, necrobiosis lipoidica, granuloma annulare, annular elastolytic giant cell granuloma, and annular sarcoidosis were considered.

Figure 1

Annular plaque with raised erythematous to violaceous margin

A biopsy was taken from an erythematous infiltrated margin of lesion over scalp after taking consent from the patient and was stained with hematoxylin and eosin, which revealed slightly atrophic epidermis and multiple confluent epithelioid granulomas having paucity of lymphocytes and focal fibrinoid necrosis [Figure 2]. Reticulin stain showed reticulin fibers surrounding the granuloma and within the granuloma [Figure 3]. Biopsy specimen was seen under polarized microscopy but did not show any foreign body granuloma. Ophthalmic examination was done, which revealed sarcoid nodules over iris and mutton fat keratic precipitates. Chest radiograph and contrast-enhanced computed tomography thorax revealed pulmonary involvement. Pulmonary function test revealed forced vital capacity and forced expiratory volume in 1 second to be reduced to 70% and 47% of normal respectively. Serum calcium was estimated with Arsenazo III method and was found to be raised to 12.5 mg% (normal: 9–11 mg%), and serum angiotensin converting enzyme levels were estimated by quantitative spectrophotometric (N-3-[2-furyl] acryloyl)-Phe-Gly-Gly test and was 48 µg/L (normal = less than 40 µg/L).

Figure 2

Photomicropgraph showing (A) slightly atrophic epidermis, (B) multiple confluent epitheloid granulomas having paucity of lymphocytes, and (C) focal fibrinoid necrosis. (H and E, ×100)

Figure 3

Photomicrograph showing reticulin fibers (arrow) surrounding the granuloma and within the granuloma. (Reticulin, ×400)

On the basis of clinical and histopathological examination, a diagnosis of annular sarcoidosis of scalp was made. The patient was started on tablet prednisolone 40 mg with marked improvement within 3 weeks [Figure 4] when steroid was tapered to 30 mg of prednisolone daily.

Figure 4

Clearance of lesion without alopecia following treatment

DISCUSSION

The diagnosis of sarcoidosis requires a compatible clinical picture, histologic demonstration of noncaseating granulomas, and exclusion of other diseases capable of producing similar histology or clinical features. The lung is the most commonly affected organ, but the skin is frequently involved.[1] Skin involvement can occur in 20%–35% of patients with sarcoidosis although it can occur without systemic involvement.[2] Skin lesions in sarcoidosis is divided into specific or nonspecific lesions. Scalp involvement in sarcoidosis is considered as a specific lesion and is uncommon. Alopecia is common in sarcoidosis and may be scarring or nonscarring in nature.[156] Alopecia due to sarcoidosis depends on the degree of destruction of hair follicles by noncaseating epithelioid cell granulomas.[1] In a review by Katta et al., only 28 cases of scalp sarcoid were reported including four cases by authors. All the four patients had systemic involvement of which two had scarring alopecia and two had nonscarring alopecia. Among these four patients only one patient had lesions restricted to scalp only.[3] Scalp sarcoidosis may occur as an erythematous lesion or may mimic discoid lupus erythematosus clinically. Histopathology plays an important role in confirming the diagnosis.[78]

Sarcoidosis may be associated with raised serum ACE and calcium levels. Raised serum ACE levels reflect the activity of the disease and are attributed to secretion of ACE by epithelioid cells of sarcoidal granuloma.[1] Macrophages of sarcoidal granulomas express 1-alpha-hydroxylase enzyme. This causes extrarenal synthesis of active form of vitamin D in sarcoidal granulomas that leads to increased intestinal absorption of calcium and raised serum calcium levels.[9]

The scalp sarcoid raises three important issues. Firstly, morphologically scalp sarcoid can present as discoid lupus, necrobiosis lipoidica, organoid nevus, as atrophic patch, with erythema, scaling, or nodules.[3] Furthermore, alopecia is common in scalp sarcoidosis and is generally scarring in nature but may be noncicatricial.[10] Our patient however, had no alopecia. Secondly, scalp involvement indicates cutaneous involvement at other sites in up to 21 of 23 cases.[3] Our case again had no cutaneous involvement beyond scalp. Thirdly, unlike cutaneous sarcoid in general, which has a systemic involvement in up to 30% of cases; the scalp sarcoid was shown to have systemic involvement in 20 of 22 cases.[3] Our case also had significant systemic involvement.

The purpose of our case presentation is to highlight the following: (A) Sarcoidosis of scalp should pre-empt a low threshold for biopsy[8] as it can mimic many dermatoses; (B) scalp sarcoid may have normal hair, nonscarring as well as scaring alopecia; (C) scalp sarcoidosis is usually but not always associated with lesions elsewhere on the skin; and (D) scalp sarcoidosis usually has a very high likelihood of systemic involvement.

Till date there is no curative treatment for sarcoidosis. Systemic corticosteroids are the drug of choice and remain the mainstay. They act by suppressing pro-inflammatory cytokines and chemokines that are responsible for granuloma formation in sarcoidosis. Other immunosuppressive agents may be used as steroid sparing agents.[12]

We thus report a rare case of annular scalp sarcoidosis without alopecia. Dermatologists should be aware to avoid missed diagnosis and inappropriate treatment.

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Conflicts of interest

There are no conflicts of interest.