Pruritic Papules in a 7‐Year‐Old Boy

A 7-year-old boy with a history of atopic dermatitis presented with pruritic, erythematous papules (~5 mm in diameter) on the extremities, abdomen, back, and soles. No vesicles or bullae were observed. The lesions appeared in intermittent flares over 2 months. Treatment-included topical betamethasone dipropionate/gentamicin 0.5 mg/g + 1 mg/g, applied twice daily in cycles based on lesion resolution, typically for 3–4 weeks. The patient also received a 2-week tapering regimen of deflazacort beginning at 30 mg daily (1 mg/kg/day). Despite treatment, lesions on the lower extremities persisted. On physical examination, erythematous papules with excoriations were widely distributed, with greater involvement of the extremities, soles and genital area (Figures 1 and 2). No mucosal involvement was noted. Resolved lesions left residual hyperpigmented and hypopigmented areas. A punch biopsy from a lesion on the right leg was done (Figures 3 and 4). Histopathological examination revealed hyperkeratosis, hypergranulosis with regular acanthosis, and vacuolization of keratinocytes in the basal layer, forming subepidermal clefts. The dermis showed a band-like lymphohistiocytic infiltrate with apoptotic bodies and occasional eosinophils. Direct immunofluorescence showed no pathological deposits of IgA, IgG, IgM, or C3. The diagnosis of bullous lichen planus (BLP) was based on histopathological findings and clinical evolution. No bullous lesions were observed initially; however, the erosions may have represented ruptured vesicobullous lesions. Laboratory workup, including complete blood count and liver and renal function tests, showed no abnormalities, and serologies for hepatitis A, B, and C viruses were negative. Approximately 1 year after the initial diagnosis, the patient experienced a severe vesicular flare on the lower extremities and soles. A 1-month tapering course of deflazacort (30 mg daily, 1 mg/kg/day) and nightly topical clobetasol propionate 0.05% achieved lesion control within 3–4 weeks. Over the past year, the flares have become less frequent and less intense, managed with topical clobetasol. Lichen planus (LP) is a chronic disease that primarily affects the skin and mucous membranes, driven by type 1T helper (Th1) cells, which produce inflammatory signals contributing to tissue damage. In addition, LP involves activity from type 17T helper (Th17) cells, which play a role in sustaining inflammation [1]. LP is uncommon in children, accounting for only 1%–4% of all cases, with the vast majority occurring in adults [2]. The most common form in children is classic LP, characterized by violaceous, pruritic papules that are symmetrically distributed on the extremities and trunk. BLP is a rare variant, in which tense blisters develop over preexisting LP lesions [3]. This variant is infrequent in children, with limited cases documented in the literature [4, 5]. In a retrospective study of 316 pediatric patients with lichen planus, none presented with the bullous variant [2]. BLP may be confused with lichen planus pemphigoides (LPP), another variant of LP. Among the clinical features that differentiate these variants, the localization of the blisters stands out: in BLP, the blisters form exclusively over preexisting LP lesions, whereas in LPP, they may appear on both LP lesions and healthy skin. Histologically, BLP presents with subepidermal blisters, vacuolar degeneration in the basal layer with apoptotic bodies, and a band-like lymphocytic infiltrate in the papillary dermis [6]. While LPP also typically shows similar subepidermal blisters there is a mixed inflammatory infiltrate that may include eosinophils, which is less common in BLP. Direct immunofluorescence is essential for distinguishing between these variants. In BLP, no antibody deposits are observed, while in LPP, IgG, and C3 deposits are detected at the dermoepidermal junction [7]. The treatment of BLP is includes high-potency topical corticosteroids to control inflammation and blister formation. In more severe cases, systemic corticosteroids or immunomodulators such as dapsone or UVB phototherapy may be used [3, 7, 8]. The choice of deflazacort for the patient was based on local clinical practice and its favorable safety profile, including a lower risk of weight gain, reduced impact on bone mineral density, and less pronounced growth suppression compared with other corticosteroids such as prednisone or dexamethasone [9]. Retinoids may have adjunctive roles, but evidence for BLP remains limited. The evolution of BLP in children is variable. The course is typically chronic, characterized by episodes of flares and remissions [1, 3]. Over time, the frequency and intensity of flares tend to decrease, as seen in chronic cases of LP and related variants. While direct evidence for this trend in BLP is limited, case studies and clinical experience suggest that the disease may gradually show reduced activity [2, 3]. In some cases, the disease improves with age, although lesions may leave post-inflammatory hyperpigmentation as a sequela. The prognosis in children is generally favorable, with good response to topical corticosteroids and, in more severe cases, systemic corticosteroids [10]. In conclusion, BLP is a rare variant of LP that should be included in the differential diagnosis of blistering diseases in childhood. The combination of clinical, histopathological, and immunological findings is essential for an accurate diagnosis. Treatment involves topical and systemic corticosteroids, with good outcomes in most cases. Regular follow-up is crucial to detect potential relapses and ensure adequate long-term management. The authors declare no conflicts of interest.