Bullous Lichen Planus of the Nails: A Case Report and Review of the Literature

Lichen planus (LP) is a chronic inflammatory disorder that can affect the skin, nails, and/or oral mucosa [1]. Bullous LP (BLP) is a rare variant of LP, which is even less common in the nails [2]. Herein, we present a case of nail BLP, associated clinical and histopathological findings, and subsequent treatment.

A 48-year-old male presented with a 10-month history of onychodystrophy of all ten fingernails. He denied any bleeding, pus, or prior nail trauma. Six months prior to the visit, he had a rash in the axilla that was confirmed by biopsy with histopathology as LP. His rash had resolved by the time he presented to us. He had no other prior medical history. On physical examination, his fingernails exhibited longitudinal ridging and white-yellow discoloration proximally (shown in Fig. 1a, b), as well as onycholysis, subungual hyperkeratosis, and v-shaped nicking of his right thumbnail (shown in Fig. 1c). There were no involvement of the toenails, no Wickham striae noted in his oral mucosa, and no patches of hair loss or scarring of the scalp. The differential diagnosis included nail psoriasis, nail LP, onychomycosis, brittle nail syndrome, and traumatic onycholysis. A longitudinal excision of the left thumbnail was performed, with histopathology showing a cell-poor subepidermal bulla (shown in Fig. 2) in association with a focal lymphocyte-mediated interface dermatitis and colloid body formation (shown in Fig. 3). C3d, C4d, and IgG4 immunohistochemical studies did not disclose any linear basement membrane zone deposits. These findings were consistent with nail LP with focal transition to nail BLP. Since more than three nails were affected, the patient was offered intramuscular triamcinolone injections. However, since he was concerned about potential systemic side effects, he opted for local treatment. He was treated with intralesional triamcinolone injections (2.5 mg/mL in 1% lidocaine using topical ethyl chloride spray) to the fingernails monthly, which was well tolerated. Improvements were noted after three treatments.

Nail LP is a chronic inflammatory disorder that may present with longitudinal ridging, red lunular discoloration, nail plate thinning, koilonychia, trachyonychia, onycholysis, subungual hyperkeratosis, nail plate atrophy, as well as anonychia and dorsal pterygium in end stages [1]. It can occur independently or concurrently with involvement of the skin and/or oral mucosa. It is considered a true nail emergency, requiring prompt and adequate treatment to prevent permanent nail loss [3]. BLP of the nails is a rare variant of nail LP. It most often occurs sporadically, but familial cases have been reported [2, 4]. Aside from typical nail LP findings, it has also been associated with nail hemorrhage. Similar to the classic form, it can involve both the fingernails and toenails, and lead to nail plate atrophy and dorsal pterygium [5]. Concomitant bulla and ulcerations of the feet and toes, white striations or plaques of the oral mucosa with erythema or ulcerations, as well as cicatricial alopecia have also been described [6].

The pathogenesis of BLP involves an autoimmune cytotoxic T-cell-mediated response targeting the basilar and parabasilar layers of the skin [2]. This leads to a dermal-epidermal separation that can be apparent both clinically and with light microscopy. Cutaneous BLP may present as vesicles or tense bullae, developing near or on pre-existing LP papules. BLP must be distinguished from LP pemphigoides (LPP), in which the formation of bullae is due to circulating autoantibodies against basement membrane antigens [7]. Cases of BLP and LPP can often be difficult to differentiate clinically, but nail and mucosal involvement are more common with BLP [2, 7].

Nail BLP has been described in 7 other case reports, as well as 1 case series including 14 patients with nail involvement (shown in Table 1) [4‒6, 8‒10]. These cases have had variable involvement of the fingernails (50.0%) and/or toenails (70.0%), with an average of 5.5 years to diagnosis (range 2 months–13 years). Toenail involvement was more common than fingernail involvement, in contrast to fingernails being more often involved than toenails in classic LP (94% vs. 54%) [1]. In general, when BLP was diagnosed early (<2 years), patients presented with onychorrhexis, nail plate hyperkeratosis, and onycholysis, similar to that of classic nail LP. When diagnosed late (5–10 years), there was often hemorrhagic crusting and partial or complete nail plate loss. Prior history or simultaneous skin involvement was noted in almost all cases (95.0%), with some having oral mucosal involvement (40.0%) and/or cicatricial alopecia (15.0%). In one case, a 30-year-old male presented with yellow, markedly thickened fingernails and toenails with longitudinal ridging, resembling yellow nail syndrome, a rare disorder characterized by a triad of yellow nails, lymphedema, and respiratory tract involvement [9]. Another BLP case in a 10-year-old boy was associated with the recombinant hepatitis B vaccine, presenting 2 months after receiving the vaccine [10]. In the case series of cutaneous BLP patients, 36 patients with BLP family history were compared to 21 patients without [4]. Of the familial BLP patients, 13 had involvement of the nails (36.1%), compared to only 1 patient (4.8%) in the nonfamilial cohort. Nail changes in the familial cases were variable and included dorsal pterygium, anonychia, onychorrhexis, nail plate hyperkeratosis, and onycholysis. Nail changes in the nonfamilial case were not described. Familial compared to nonfamilial cases had earlier age of BLP onset (average 9.6 vs. 21.1 years old, respectively), as well as a more prolonged course (average 30.1 vs. 11.3 years, respectively). Notably, our patient was diagnosed earlier (10 months) compared to other BLP patients (average 5.5 years), but similar to almost all previous nail BLP cases, he had prior cutaneous LP involvement. Our patient did not have involvement of the oral mucosa or scalp. Given the often late diagnosis of nail BLP and variable involvement of skin, scalp, and mucosa, increased awareness and a high index of suspicion for this condition are necessary. Specifically, diagnosis of the bullous variant of nail LP may frequently be missed, given the similar clinical presentation to that of classical nail LP, as illustrated with our patient. Overall, both nail LP and nail BLP may be more common than currently reported. Further workup and biopsy are warranted in any suspected cases.

Accurate diagnosis of nail LP, including nail BLP, requires a biopsy with histopathological correlation 11. A longitudinal excision is suggested to ensure sufficient sampling of nail matrix and nail bed. Characteristic histopathologic findings of nail LP include acquisition of a granular cell layer with hypergranulosis of the nail matrix and bed epithelium. There is also a band-like lymphocytic infiltrate within the superficial corium, with lymphocyte apposition to the basal layer keratinocytes and ensuing epithelial destruction [2]. BLP histopathological findings include these classical LP changes, as well as formation of subepidermal bullae with prominent collections of colloid bodies [7]. Extensive T-cell-mediated injury to the basal layer results in bullae formation referred to as subepidermal Max-Joseph spaces. Colloid or civatte bodies are cytoplasmic remnants of apoptotic keratinocytes that can be identified in the superficial dermis [2]. In differentiating BLP from LPP, colloid bodies are often more prominent in BLP. With LPP, C3d, C4d, and IgG4 studies conducted on paraffin-embedded tissue, as well as IgG and C3 direct immunofluorescence, will show a linear homogeneous deposition pattern within the epidermal basement membrane zone [7].

Since nail BLP is extremely rare, there are no guidelines or consensus on management, with only two cases in our review reporting treatment. A 60-year-old male with nail BLP was treated with an unspecified topical steroid-antibiotic combination for 6 weeks, resulting in resolution of hemorrhagic crusting and nail fold swelling [5]. A 30-year-old male with nail BLP was treated with chloroquine diphosphate for 11 weeks, but without improvement [9]. Our patient was treated with intralesional triamcinolone injections, commonly used in nail LP, but not previously reported for bullous forms [1]. Topical treatments are rarely effective in nail LP due to limited absorption through the nail plate. Intralesional/intramuscular triamcinolone injections have thus been recommended as first-line therapies, followed by oral retinoids or immunosuppressive agents [12]. We demonstrate efficacy of intralesional triamcinolone injections for the bullous variant, in addition to classical nail LP.

In summary, BLP is an LP variant that can rarely involve the nail. Our case corroborates prior literature on nail BLP and emphasizes the need for a high index of suspicion for the condition, given the frequent delay in diagnosis. We also demonstrate intralesional triamcinolone injections to the nails as a successful management option for this case of nail BLP. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000533386).

Ethical approval is not required for this study in accordance with national guidelines. Written informed consent was obtained from patient for publication of details of their medical case and any accompanying images.

JKH and CCM have no conflicts of interest to declare. SRL has served as a consultant for Hoth Therapeutics, Ortho-Dermatologics, Belle Torus Corporation and Moberg Pharmaceuticals.

No funding was used for this study.

J.K.H., C.C.M., and S.R.L. contributed to writing and editing of this manuscript.

All data generated or analyzed during this study are included in this article and its online supplementary material. Further inquiries can be directed to the corresponding author.