Discrepancies among clinical, histological and immunological findings in IgA pemphigus: a case report and literature survey

IgA pemphigus is a rare variant of pemphigus presented clinically with vesiculopustular skin lesions, and histopathologically neutrophil infiltration and acantholysis in the epidermis. Moreover, circulating IgA autoantibodies target cell surface components of the epidermis.
According to clinical, histopathological and direct immunofluorescence features, IgA pemphigus is subdivided into subcorneal pustular dermatosis (SPD) type reactive with desmocollin 1 (Dsc1) [1] and intraepidermal neutrophilic IgA dermatosis (IEN) type reactive with an unknown antigen. However, in some reported cases of IEN type IgA pemphigus, the IgA anti-cell surface autoantibodies reacted with desmoglein 1 (Dsg1) or Dsg3 [2, 3], which are widely accepted to be the target antigens in pemphigus foliaceus and pemphigus vulgaris, respectively.
Here, we present a case of IgA pemphigus with histopathological features typical of the SPD type and immunological characteristics of the IEN type with anti-Dsg3 antibodies, and a review of the literature.
An 87-year-old male of Polish origin presented erosions in the oral mucosa and in intertriginous areas. The patient had numerous internal disorders, including ischemic cardiomyopathy, type 2 diabetes, abdominal aortic aneurysm, partial stomach resection because of peptic ulcer disease, colitis, diverticular disease, iron deficiency anemia, hemorrhoids and prostatic hypertrophy, and took torasemide, finasteride, acetylsalicylic acid, pantoprazole, ramipril and nebivolol.
The patient was initially treated in the Department of Internal Medicine with topical antibiotics and topical glucocorticosteroids with no improvement. Oral prednisolone in a dose of 10 mg/day for 2 weeks was not effective, either. The unsuccessful treatment and polymorphic skin lesions led to the hypothesis of paraneoplastic disorder. Therefore, abdominal ultrasonography, gastroscopy and chest X-ray were performed and showed no abnormalities. However, the fecal blood test was positive in the patient and colonoscopy evaluation revealed colitis. Histopathological evaluation of the patient skin indicated pyodermitis, whereas the results of direct and indirect immunofluorescence were negative.
Three months later, the patient was referred to the Department of Dermatology. Physical examination revealed annular erythematous skin lesions with erosions and pustules on the abdomen, groins, buttocks and right armpit. Groins were most severely affected (Figure...


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