A 17-year-old woman with bullous lesions.

A 17-year-old woman with no significant medical history presented with mildly pruritic vesiculous eruption displayed on her trunk, arms, and scalp with bullae grouped together and isolated, on erythematous base. [Figures 1] and 2]. On the buccal mucosa there were superficial erosions. On her palms and forearms, she had target-like, erythematous lesions. [Figure 3]. The symptomatology began 8 months ago and its evolution was slow, but progressive.

Figure 1

Grouped bullous lesions on trunk

Figure 2

Grouped bullous lesions below umbilicus

Figure 3

Target like erythematous lesions on palm

Laboratory findings revealed an acute inflammatory syndrome (leukocytosis with neutrophillia, elevated PCR). Biopsies were taken from the lesional skin (for hematoxylin eosin staining), and from apparently normal skin (for direct immunofluorescence). The histological slide evidenced an atrophic epidermis with deep bullae and an increased eosinophilic infiltrate), while the direct immunofluorescence was positive for IgG, IgM, and C3, with band - like deposits along the basement membrane. [Figure 4].

Figure 4

Showing IgG, IgM, and C3, with band - like deposits along the basement membrane

Question

What is your diagnosis?

Answer

Bullous Pemphigoid

Discussion

The peculiarity of the case consists of the fact that the clinical aspect was suggestive of a diagnosis of dermatitis herpetiformis (the age, the location of lesions, grouped together, flaccid bullae, mucosa involvement, the inflammatory syndrome). However, the histopathological findings excluded dermatitis herpetiformis. There was still a debate if it was bullous pemphigoid or epidermolysis bullosa aquisita, as both diseases give a similar aspect at direct immunofluorescence. The hematoxylin and eosin stained slide with plenty of eosinophils suggested the final diagnosis.

Bullous pemphigoid is an autoimmune disorder presenting as a chronic bullous eruption, mostly in patients over 60 years of age. Histopathological examination describes subepidermal bulla with neutrophils, eosinophils, and lymphocytes in the papillary dermis. More specific are the eosinophils lined under the basement membrane. In direct immunofluorescence, linear IgG deposits are located along the basement membrane zone. Also, C3 may occur in the absence of IgG. Circulating antibasement membrane IgG antibodies are detected by IIF in 70% of patients. Titers do not correlate with the course of disease. Autoantibodies in bullous pemphigoid recognize two types of antigens. BPAG1 is a 230 – kDa glycoprotein that has high homology with desmoplakin I/II and is part of hemidesmosomes. BPAG2 is a transmembranous 180 - kDa polypeptide (type XVII collagen).[1] There are a few reported cases with both clinical and histopathological similarities with dermatitis herpetiformis, but with direct imunofluorescence pleading for bullous pemphigoid.[2]

Prodromal bullous pemphigoid is a very challenging entity for the clinician to diagnose as it appears in a multitude of clinical shapes, often mimicking another pathology. A recent study shows that 9.4% of prodromal bullous pemphigoid cases present themselves as dermatitis herpetiformis - like lesions.[3]

The treatment in bullous pemphigoid consists of corticosteroids as the first line of therapy, which may be associated with many immunosuppressive drugs (dapsone, azathioprine, methotrexate, cyclophosphamide). Last options for treatment resistant cases may be i.v. immunoglobulins or plasmapheresis.[4]

Our patient was treated initially with oral and topical corticosteroids, with partial clinical remissions. At doses below 30 mg prednisone per day the lesions reappeared. Therefore, we combined the prednisone with dapsone 50 mg per day and thus we were able to reduce the steroid doses. Presently, under 50 mg dapsone per day and 5 mg prednisone per day, the patient has been free of disease for the last 4 months.