An otherwise healthy 67-year-old woman presented to our Outpatient Consultation for Nail Diseases of the Department of Dermatology of the University of Bologna for a nail alteration of her first digit of the right hand with several months history. At the time of our consultation, longitudinal ridges, splinter haemorrhages, mild onycholysis, and red lunula alteration were observed (shown in Fig. 1a).

Fig. 1.

a Clinical presentation of the first finger of the right hand with longitudinal ridges, splinter haemorrhages, mild onycholysis, and red lunula. On the third finger of the right hand, a pinkish-orange papule is noted. b Onychoscopy displays the presence of red lunula (black star) with longitudinal red strikes with serpiginous aspect (white arrows) and erythronychia (black arrow). c The nail bed reveal a yellowish-orange colour (white star) with evident linear and serpiginous capillaries and splinter haemorrhages (white triangle). d Dermoscopy of pink-orange papular lesion of the third finger of the right hand show a yellow-orange background and linear vessels arranged in a radial pattern with serpiginous aspects (black triangle).

Fig. 1.

a Clinical presentation of the first finger of the right hand with longitudinal ridges, splinter haemorrhages, mild onycholysis, and red lunula. On the third finger of the right hand, a pinkish-orange papule is noted. b Onychoscopy displays the presence of red lunula (black star) with longitudinal red strikes with serpiginous aspect (white arrows) and erythronychia (black arrow). c The nail bed reveal a yellowish-orange colour (white star) with evident linear and serpiginous capillaries and splinter haemorrhages (white triangle). d Dermoscopy of pink-orange papular lesion of the third finger of the right hand show a yellow-orange background and linear vessels arranged in a radial pattern with serpiginous aspects (black triangle).

Close modal

Onychoscopy with an ultrasound gel as interface was then performed and revealed the presence of red lunula with longitudinal red strikes with serpiginous aspect and erythronychia (shown in Fig. 1b). The nail bed had a yellowish-orange colour with evident linear and serpiginous capillaries and splinter haemorrhages (shown in Fig. 1c).

A careful skin examination revealed the presence of additional pink-orange papular lesions located on the third finger of the right hand (shown in Fig. 1a) and on the dorsum of the nose that at dermoscopy showed a yellowish-orange background and linear vessels arranged in a radial pattern with the same serpiginous aspect (shown in Fig. 1d). A biopsy of the skin papule on the right hand, on the nose, and a longitudinal biopsy of the nail unit were scheduled. The histology showed nodular granulomatous infiltrate characterized by collection of epithelioid histiocytes; some are multinucleate with a few lymphocytes in the dermis of proximal nail fold and in the dermis at the level of the nail matrix (shown in Fig. 2). Periodic acid-Schiff staining showed no fungi. Ziehl-Neelsen staining revealed no acid-fast bacilli.

Fig. 2.

a Longitudinal section of the nail unit. Nodular granulomatous infiltrate in the dermis at nail proximal fold and focally in the dermis at the level of nail matrix (H&E. ×1). b, c Collection of epithelioid histiocytes surrounded by few lymphocytes (b H&E. ×25; c H&E. ×35).

Fig. 2.

a Longitudinal section of the nail unit. Nodular granulomatous infiltrate in the dermis at nail proximal fold and focally in the dermis at the level of nail matrix (H&E. ×1). b, c Collection of epithelioid histiocytes surrounded by few lymphocytes (b H&E. ×25; c H&E. ×35).

Close modal

What Is Your Diagnosis?

Systemic sarcoidosis with nail involvement.

During a dermatologic consultation, examination of the nails is always recommended also if this special site is not requested by the patient. Nail examination can be signs of different systemic or cutaneous disorders and be crucial for the differential diagnosis. In this report, we describe a case of systemic sarcoidosis with nail involvement to emphasize how a nail observation can mirror a more serious systemic disease in which early diagnosis is critical.

Sarcoidosis is a multi-organ systemic inflammatory disease of unknown cause, characterized histopathologically by non-caseating epithelioid cell granulomas, usually without surrounding lymphocytic infiltration, called “naked” granulomas. Although skin involvement is reported in 10–35% of cases, nail abnormalities are considered a rare occurrence, with a prevalence of 0.3–1.6%, but often conceals a systemic involvement [1].

Nail changes in sarcoidosis are related to the presence of sarcoidal granulomas in the dermis and the severity of nail dystrophy reflects the size and location of the granulomas. The nail changes are non-specific and can present with a broad spectrum of manifestations due to damage resulting from matrix compression, including longitudinal ridging, trachyonychia, pachyonychia, onycholysis, onychorrhexis or onychoschisis, pitting, nail atrophy, and pterygium. Other features such as subungual hyperkeratosis, splinter haemorrhages, and red or brown discolouration have also been reported [2].

Periungual skin abnormalities of the proximal nail fold, nail bed, and hyponychium may be related to sarcoidosis of the skin adjacent to the nail and/or lupus pernio. These nail patterns are non-specific and may be variously observed in other conditions such as lichen planus, psoriasis, onychomycosis, bacterial infections, or traumatic onycholysis.

The clinical variability of cutaneous sarcoidosis makes it challenging to correctly diagnose it. Dermoscopy is an extremely useful tool to establish the diagnostic suspicion, then confirmed by histological examination. Translucent orange-yellowish globular-like or structureless areas in combination with linear vessels have been correlated with underlying granulomas and are suggestive for a diagnosis of granulomatous disease such as sarcoidosis [3]. In nail sarcoidosis, onychoscopy should be performed with the use of an interface such as an ultrasound gel, in order to better examine the nail colour and appreciate the presence of disease-specific features.

Red (mottled) lunula, which refers to irregular dotted or diffuse redness of the lunula, as well as longitudinal erythronychia bands (red streaks), are due to dilation of the distal nail matrix capillaries and reflect the grade of local inflammation. The nail bed may be diffusely yellow-orange with evident dilated vessels that may be accompanied by splinter haemorrhages and resemble the dermoscopic appearance of cutaneous papules.

The final diagnosis of nail sarcoidosis requires histological examination of nail bed detecting non-caseating sarcoid granulomas, specific for sarcoidosis. Sarcoidosis of the nails is often associated with bone alterations of the underlying distal phalanges, so further radiological investigation is required. Sarcoid dactylitis often accompanies nail sarcoidosis and may involve one or more fingers. It manifests by pain and “sausage-like” swelling of the phalanx; in rare cases, a necrotizing form with ulceration has been documented [4].

As reported by Momen and Al-Niaimi [2], bone cysts are the most frequent bone lesions associated to nail sarcoidosis and are described in 60% of patients. In addition, they demonstrated that nail sarcoidosis presents systemic involvement in the totality of 33 cases reviewed: lupus pernio, dactylitis, lymphadenopathy, and pulmonary fibrosis were present in 36, 27, 33, and 18% of patients, respectively. Among the 33 cases, 17 of the 20 patients (85%) showed phalangeal lesions on radiographs, describing a simultaneous scenario of nail and bone sarcoidosis [2].

Radiolucent cyst-like lesions with a lacy or honeycombed trabecular pattern are the classic phalangeal manifestation of bone resorption due to sarcoidosis. More rarely, acro-osteolysis and pathological fractures are described. These bone changes in most patients are usually asymptomatic but are already a sign of chronic or systemic disease. A retrospective study involving 20 patients with bone sarcoidosis showed that axial skeletal involvement is the most common form, detected in 90 % of cases by MRI or positron emission tomography, while only 10% of cases showed a phalangeal localization [5].

Because bone and systemic involvement may be asymptomatic or paucisymptomatic but may influence the staging of the disease, radiographic examination of the hands or feet and screening for systemic involvement with at least one chest radiograph are recommended in patients with nail sarcoidosis. There are no clear guidelines for the treatment of nail and bone sarcoidosis due to the rarity of involvement at these sites.

Often, these conditions conceal systemic disease in most patients; therefore, the most severely affected organ usually dictates the treatment regimen, and frequently nail and bone disorders respond to therapy. In case of nail involvement without signs of systemic disease, topical clobetasol in occlusion on the affected nails may be a therapeutic option [6]. In case of persistence or systemic involvement, antimalarials, tetracyclines, or methotrexate, can be successfully administered [7]. More recently, inhibitors of tumour necrosis factor alpha (TNF-α) have also been used with significant efficacy in resolving bone lesions [8].

The use of dermoscopy in nail disorders is quite recent and is growing in importance in clinical practice. To date, onychoscopy of nail sarcoidosis has never been described in the literature. Some features such as the yellowish-orange background and linear vessels with serpiginous aspect on nail bed are reminiscent of dermoscopy of skin lesions. It may also present with red lunula, longitudinal erythronychia with irregular dotted or diffuse redness of the lunula area, an indirect sign of inflammation. This case highlights the importance of nail dermoscopy in clinical practice; it can help diagnose nail disorders and in addition, it can mirror a systemic disorder where early diagnosis is critical. Examining the skin in addition to the nails, and considering radiologic evaluation when prudent, is important to complete this evaluation.

The authors state that they have obtained written informed consent to publish the reported case and clinical images from the patient through a signed copy of our patient consent permission form. The authors confirm that the ethical policies of the journal, as noted on the journal’s author guidelines page, have been adhered to. As per the institute’s guideline, the study does not require ethics approval because it is a description of only one case report.

The authors have no conflicts of interest to declare.

The authors have received no external funding.

All authors have contributed significantly and seen and approved the final version of the submitted paper. Bianca Maria Piraccini, Michela V.R. Starace, and Michelangelo La Placa defined the design and intellectual content of the paper. Cosimo Misciali provided the histopathological aspects. Roberta Vezzoni wrote the draft, edited manuscript and figures, and prepared them for submission.

All data analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author. This manuscript has not been published or submitted for publication elsewhere.

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