Direct Immunofluorescence of Mechanobullous Epidermolysis Bullosa Acquisita, Porphyria Cutanea Tarda and Pseudoporphyria

Abstract

Mechanobullous epidermolysis bullosa acquisita (mEBA) can have a clinical presentation that is very similar to other blistering diseases, such as porphyria cutanea tarda (PCT) and pseudoporphyria. Direct immunofluorescence is an important feature in the diagnosis of mEBA, although features that overlap with PCT and pseudoporphyria have been reported. This retrospective observational study investigated whether direct immunofluorescence can discriminate mEBA from PCT and pseudoporphyria. Biopsies of 13 patients with mEBA, 10 with PCT and 10 with pseudoporphyria were included. In 7 cases of PCT and 4 of pseudoporphyria, direct immunofluorescence showed a pattern at the dermal-epidermal junction that appeared similar to the u-serrated pattern in mEBA. Vessel wall depositions were observed in all 3 diseases, but were more frequent and more intense in PCT and pseudoporphyria than in mEBA. Careful examination of direct immunofluorescence of mEBA vs. PCT and pseudoporphyria revealed different staining patterns, although overlapping features were present. Therefore, integrating all clinical and laboratory data is essential to differentiate between mEBA, PCT and pseudoporphyria.

Epidermolysis bullosa acquisita

“…Homogeneous deposits of IgG, IgM, IgA at the BMZ and vessel wall are the most common DIF findings in PCT and help in its differentiation from EBA. 53 …”

Pseudoporphyria—a diagnostic challenge: A case series and a proposed diagnostic algorithm

“…3 It is hypothesized that certain photosensitizing drugs could act directly , in a similar way to porphyrins, depositing on specific skin structures leading to their subsequent photoactivation and the development of blisters. 1,4 Clinical findings include erosions, vesicles, bullae, skin fragility, milia, and scarring on sun-exposed skin. Lesions often present on 2).…”

“…Histologically, pseudoporphyria is similar to PCT 5 and presents with pauci-inflammatory subepidermal blisters, festooning of dermal papillae and the presence of caterpillar bodies. 4,6,7 DIF examination can show a linear u-serrated pattern, 4 or less frequently an n-serrated pattern, of IgG and C3 deposits on the DEMB and the vascular basement membrane, the latter being less commonly present in ABD. 4 DIF can be negative in approximately 1/3 of cases.…”

“…4,6,7 DIF examination can show a linear u-serrated pattern, 4 or less frequently an n-serrated pattern, of IgG and C3 deposits on the DEMB and the vascular basement membrane, the latter being less commonly present in ABD. 4 DIF can be negative in approximately 1/3 of cases.…”

Blisters and Crusts on the Dorsum of the Hands: A Quiz

“…In this case the patient shows annular blisters with almost targetoid-like appearance; hence, further differential diagnosis include linear IgA dermatosis, bullous lupus, bullous erythema multiforme and bullous pemphigoid. Normal urine porphyrins and the presence of specific serological autoantibodies, as well as different histological features, should allow differentiation from PCT ( 2 , 4 , 6 ). Pseudoporphyria is another differential diagnosis.…”