Generalized pruritic blisters and bullous lesions

Pemphigus vulgaris is characterized by nonpruritic, flaccid, painful blisters. This condition usually begins with manifestation of painful oral lesions that evolve into skin blisters. Some patients can develop mucocutaneous lesions.¹ Nikolsky sign is positive in these cases. Light microscopy would show intra-­epidermal bullae.

Dermatitis herpetiformis. This condition—usually affecting middle-age patients—is associated with severe pruritis and burning. It may start with a few pruritic papules or vesicles that later evolve into urticarial papules, vesicles, or bullae. Dermatitis herpetiformis can resemble herpes simplex virus. It can also be associated with gluten-sensitive enteropathy and small bowel lymphoma.¹ DIF of a biopsy sample would show granular deposition of IgA within the tips of the dermal papillae and along the basement membrane of perilesional skin.¹

Epidermolysis bullosa acquisita is a rare, severe, chronic condition with subepidermal mucocutaneous blistering.¹ It is associated with skin fragility and spontaneous trauma-induced blisters that heal with scar formation and milia. IgG autoantibodies reacting to proteins in the basement membrane zone can cause the disease. It is also associated with Crohn disease.¹ DIF findings are similar in BP, but they are differentiated by location of IgG deposits; they can be found on the dermal side of separation in epidermolysis bullosa acquisita, as compared with the epidermal side in BP.¹

How to make the Dx in 3 steps

To effectively diagnose and classify BP, use the following 3-step method:

1. Establish the presence of 3 of 4 ­clinical characteristics: patient’s age > 60 years, absence of atrophic scars, absence of mucosal involvement, and absence of bullous lesions on the head and neck.
2. Order light microscopy. Findings should be consistent with eosinophils and neutrophils containing subepidermal bullae.
3. Order a punch biopsy to obtain a perilesional specimen. DIF of the biopsy findings should feature linear deposits of IgG with or without C3 along the dermo-epidermal junction. This step is essential for an accurate diagnosis.

Depending on the severity of disease, treatment can include the use of potent topical corticosteroids alone or in combination with systemic corticosteroids and antiinflammatory antibiotics.

There also is benefit in ordering supplemental studies, such as an enzyme-linked immunosorbent assay for the detection of anti-BP180 or anti-BP230 IgG autoantibodies.⁷ However, for this patient, we did not order this study.

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