A case of linear IgA disease in a child with IgA and IgG circulating antibodies directed to BPAg2

Linear Immunoglobulin a Bullous Dermatosis in Children

Linear Immunoglobulin A Bullous Disease (LABD) is a rare dermatosis whose pathomechanisms are not yet completely understood. LABD has different features characterizing adults and children in terms of potential triggers, clinical manifestations, and prognosis. The aim of the present study is to review all neonatal and pediatric cases of LABD and summarize the major characteristics. Childhood LABD is mainly idiopathic with a benign prognosis. Neonatal cases are difficult to differentiate from infectious diseases and usually have a poor prognosis. Drugs are one of the possible triggers that can activate autoimmune responses through antigen mimicry and epitope spreading as well as different stimuli (e.g., infections, inflammatory diseases, trauma). The gold standard for the diagnosis is based on direct immunofluorescence. Prognosis is generally favorable but often depends on the prompt dermatological diagnosis, treatment and follow-up guaranteed by a multidisciplinary team, including pediatricians for this group of age.

Linear IgA bullous dermatosis in adults and children: a clinical and immunopathological study of 38 patients

BACKGROUND

Linear IgA bullous dermatosis (LABD) is a rare autoimmune subepithelial vesiculobullous disease due to IgA autoantibodies directed against different antigens of the basement membrane zone (BMZ) of the skin and/or mucosae. It affects mainly preschool-aged children and adults, with only few studies on large series. The aim of this study was to assess possible differences between adults and children regarding clinical presentation, immunopathologic features, management and course of the disease.

METHODS

A retrospective review of 38 LABD patients, followed-up from November 2006 to September 2018, was performed.

RESULTS

Of 38 patients, 27 were adults and 11 children. Mean age at diagnosis was 5.4 years and 60.6 years in the pediatric and adult group, respectively. Considering both groups, limbs were the most commonly involved site (73.7%), followed by trunk (55.3%), head (36.8%) and buttocks (13.2%). Interestingly, head (p = 0.008), particularly perioral (p = 0.001), involvement, as well as "string of pearls" arrangement (p = 0.03), were more prevalent in children. Mucosal involvement was seen in 9 (23.7%) patients and was more frequent in children than adults (45.5% vs 14.8%, respectively, p = 0.09). Linear IgA deposits along the BMZ were observed in 30 patients (78.9%), while linear/granular IgA deposits in 8 patients (21.1%). Dapsone was the most commonly used drug (78.9%) and complete remission was achieved in most cases (81.6%).

CONCLUSIONS

Our epidemiological and clinicopathological findings relative to a large cohort of LABD patients are mostly consistent with the literature data. Interestingly, head, notably perioral, involvement and "string of pearls" arrangement occurred more frequently in the paediatric than adult group. The above clinical parameters may be regarded as diagnostic tools for LABD in children.

Histopathology of Cutaneous Inflammatory Disorders in Children

Inflammatory dermatoses encompass a variety of histologic patterns that affect different portions of the skin. In spongiotic, psoriasiform, lichenoid, pityriasiform, and blistering disorders, there are predominately epidermal and junctional activities with variable superficial dermal inflammation. Hypersensitivity reactions can show either epidermal or mostly dermal changes depending on whether the exposure of the exogenous allergen occurs through an external or internal route, respectively. Exceptions include erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis, where the etiology is often due to infection or ingested medications, but the histologic features are almost exclusively confined to the epidermis and dermoepidermal junction. Autoimmune disorders are unique in that lesions typically incorporate a mixture of epidermal and dermal inflammatory patterns with periadnexal inflammation, while the vast majority of vasculitis/vasculopathy and alopecia have changes limited to only the vessels and hair follicles, respectively. It is critical to recognize that a relatively limited number of histologic patterns are seen in a large array of clinical entities. Therefore, clinicopathologic correlation and careful examination of histologic details are of the utmost importance when evaluating skin biopsies for inflammatory disorders.

BP180 Is Critical in the Autoimmunity of Bullous Pemphigoid

Bullous pemphigoid (BP) is by far the most common autoimmune blistering dermatosis that mainly occurs in the elderly. The BP180 is a transmembrane glycoprotein, which is highly immunodominant in BP. The structure and location of BP180 indicate that it is a significant autoantigen and plays a key role in blister formation. Autoantibodies from BP patients react with BP180, which leads to its degradation and this has been regarded as the central event in BP pathogenesis. The consequent blister formation involves the activation of complement-dependent or -independent signals, as well as inflammatory pathways induced by BP180/anti-BP180 autoantibody interaction. As a multi-epitope molecule, BP180 can cause dermal-epidermal separation via combining each epitope with specific immunoglobulin, which also facilitates blister formation. In addition, some inflammatory factors can directly deplete BP180, thereby leading to fragility of the dermal-epidermal junction and blister formation. This review summarizes recent investigations on the role of BP180 in BP pathogenesis to determine the potential targets for the treatment of patients with BP.

Linear IgA disease: clinical presentation, diagnosis, and pathogenesis

Linear IgA disease is one of the rarer subepidermal blistering diseases. Linear IgA disease is a chronic, acquired, autoimmune blistering disease that is characterized by subepidermal blistering and linear deposition of IgA basement membrane antibodies. The disease affects both children and adults and, although there are some differences in their clinical presentations, there is considerable overlap with shared immunopathology and immunogenetics.

Linear IgA/IgG bullous dermatosis: successful treatment with dapsone and mycophenolate mofetil

A 21-year-old female presenting linear IgA and IgG disease initially responded well to dapsone therapy. However, the treatment with dapsone was withdrawn due to severe anemia induced by malaria, which led to worsening of the clinical picture. Although prednisone and methylprednisolone were tried, the patient responded only to the association of dapsone and mycophenolate mofetil.

Linear IgA disease: clinical presentation, diagnosis, and pathogenesis

Linear IgA disease is one of the rarer subepidermal blistering diseases. Linear IgA disease is a chronic, acquired, autoimmune blistering disease that is characterized by subepidermal blistering and linear deposition of IgA basement membrane antibodies. The disease affects both children and adults and, although there are some differences in their clinical presentations, there is considerable overlap with shared immunopathology and immunogenetics.