Autoimmune bullous diseases (AIBD) are chronic disorders associated with significant morbidity and even mortality, for which the 19 dermatologic departments in Austria apply standard modalities to provide state-of-the-art diagnosis and treatment. Most of the affected individuals are initially treated on an inpatient basis, with follow-up done in specialized outpatient clinics or in private practices. A well-established system of care for AIBD patients is thus available nationwide. Considering the significant morbidity and mortality but also rareness of AIBD, national and international standardization of AIBD administration in registries is a major requirement of further improvement in patient care.
Autoimmune bullous diseases
Autoimmune bullous diseases (AIBD) refer to a group of rare (ie, orphan disease) tissue-specific autoimmune disorders targeting the structural and functional integrity of skin and mucous membranes. Driven by genetic susceptibility, both the humoral and cellular immune systems are synergistically involved in the pathogenesis of these potentially life-threatening entities. As a unifying feature, circulating autoantibodies induce intraepidermal, junctional (in lamina lucida of the basement membrane zone [BMZ]), or dermolytic (below lamina densa of the BMZ) cleavage, leading to characteristic cutaneous blisters and erosions. This process is supposed to occur by mechanisms of steric hindrance or induction of inflammatory signal transduction cascades as well as apoptotic pathways.
Many AIBD have a chronic, relapsing, and often progressive course, and extensive disease may be complicated by scarring, superinfections, multisystemic involvement, and catabolism. This process causes significant morbidity (as for example by blindness, Fig. 1 ) and even mortality (also by side effects of therapy), as well as considerably high costs because treatment and regular follow-ups may be expensive (eg, €2200 for 500 mg rituximab), intensive, and lifelong. Current treatment modalities, including corticosteroids and corticosteroid-sparing adjuvant immunosuppressive or immunomodulatory agents, are effective, but a remarkable side-effect profile may limit their applicability. Moreover, most of the drugs have never been evaluated in large controlled studies, due to the rareness of AIBD.
Therefore, collecting data of affected individuals in national and international registries on AIBD, covering clinical, diagnostic, and therapeutic data as well as biobanking, should provide a comprehensive database to facilitate clinical and investigative studies as a further step toward better patient care.
Epidemiology of AIBD in Austria
Currently lacking an integrative administrative approach in Austria, exact data on the national epidemiology of AIBD are largely missing. Between 1990 and 2007, the authors’ own departmental registry in Salzburg, serving a catchment area of about 650,000 inhabitants from Salzburg, neighboring districts of Upper Austria, and Bavaria, enrolled a total of 270 AIBD patients ( Fig. 2 ). About 50% of these patients were (newly) diagnosed for bullous pemphigoid (BP) and another 10% for each pemphigus disease (including pemphigus vulgaris [PV], and pemphigus foliaceus [PF]), cicatricial (mucous membrane) pemphigoid (CP) and epidermolysis bullosa acquisita (EBA). The remainder were classified as suffering from dermatitis herpetiformis Duhring (DHD, 7%), linear IgA dermatosis (LAD, 4%), lichen ruber pemphigoides (LRP, 3%) and, even more rarely, gestational pemphigoid (GP, 2%), IgA pemphigus (IgA-P, 1%), and paraneoplastic pemphigus (PNP, <1%).
