Although reflectance confocal microscopy (RCT) and optical coherence tomography (OCT) provide useful information for a rapid noninvasive diagnosis and optimal biopsy site of bullous pemphigoid (BP) and pemphigus, histopathologic and immunologic examinations remain the gold standard for establishing a final diagnosis, according to the results of an observational retrospective multicenter study published in the Journal of the European Academy of Dermatology and Venereology.

The investigators sought to evaluate the characteristics of BP and pemphigus with RCM and OCT in order to offer a quick noninvasive bedside diagnosis. The study was also designed to evaluate the detectability of clinically nonvisible lesions.

Patients who had lesions suspicious for BP or pemphigus underwent clinical assessment, RCM, OCT, blood tests, and skin biopsy for histologic and direct immunofluorescence examinations from January 2014 to December 2015.

Patients age ≥18 with clinically suspicious BP or pemphigus lesions were sent for additional noninvasive diagnostic examination and were considered for study inclusion. Overall, a total of 72 lesions (48 BP; 24 pemphigus) from 24 patients (16 BP; 8 pemphigus) were evaluated. Lesions were located mainly (75%) on the trunk and upper limbs. In addition, apparently unaffected skin at 2 different locations (surface area near [1 to 2 cm] and far [2 to 3 cm]) from each lesion was examined by RCM and OCT for subclinical lesion detectability.

With OCT, inflammatory cells inside blisters were detected more often in patients with BP than in patients with pemphigus (62.5% vs 25%, respectively). Fibrin deposition inside blisters was observed only in patients with BP (62.5%).

RCM detected subepidermal and intraepidermal blisters in 75% and 50% of patients with BP and pemphigus, respectively. With OCT, the exact blister level was identified in all patients. Acantholytic cells were observed only with RCM in 62.5% of patients with pemphigus. Fibrin deposition inside blisters was detected only in patients with BP with the use of both RCM and OCT.

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A total of 144 images of clinically healthy skin were examined, with 96 and 48 images of apparently unaffected skin obtained with RCM and OCT from patients with BP and pemphigus, respectively. In patients with BP, subclinical blisters were detected in clinically healthy skin in 9.4% (9 of 96) of the images, whereas in patients with pemphigus, subclinical blisters were observed in 20.8% (10 of 48) of the images.

The investigators concluded that the use of RCM plus OCT in patients with BP and pemphigus is optimal, as it combines the higher resolution of RCM with the greater penetration depth of OCT. Specifically, OCT allows a clear definition of the anatomic location of the bulla and enables the identification of subclinical lesions, whereas RCM detects some microscopic parameters that can be used in the differential diagnosis of vesicobullous diseases.

Reference

Mandel VD, Cinotti E, Benati E, et al. Reflectance confocal microscopy and optical coherence tomography for the diagnosis of bullous pemphigoid and pemphigus and surrounding sub-clinical lesions [published online January 16, 2018]. J Eur Acad Dermatol Venereol. doi:10.1111/jdv.14795