Half and half blisters in pemphigus vulgaris: A diagnostic quandary.

Sir,

A 28-year-old woman was admitted in our department with a one month history of recurrent, multiple, pruritic, fluid-filled lesions over her abdomen, which gradually extended to involve her chest, back, arms, legs, and oral cavity. Two weeks prior, she noticed pustular lesions over her trunk and limbs that would rupture spontaneously leaving behind painful erosions. There was no history of genital lesions, drug intake, exacerbation upon sun exposure, or family history of similar lesions. Before being admitted, the patient had received antibiotic therapy; however, there was no response. At the time of admission the patient was febrile; all other vitals were stable. Systemic examination was normal. Dermatologic examination revealed multiple vesicles, bullae, and crusted erosions over an erythematous base on her trunk and limbs. Some of these were filled with clear fluid, whereas others contained both clear and yellow fluid in the upper and lower parts, respectively, forming a hypopyon, that resulted in an appearance resembling “half -half” blisters [Figure 1a and b]. Oral mucosa showed irregular erosions over the soft palate. Nikolsky's sign was positive. General laboratory screening was within normal limits. Tzanck smear showed the presence of acantholytic cells [Figure 2a]. Pus culture demonstrated multiple gram-positive cocci. Skin biopsy taken from a fresh half and half blister revealed suprabasal acantholysis with a row of tomb stone appearance of the basal cells [Figure 2b]. Direct immunoflourescence of perilesional biopsy showed intercellular IgG and C3 deposits giving a classical “fish net appearance” [Figure 2c]. In view of the above clinical picture, histopathology, and immunoflourescence findings, a diagnosis of pemphigus vulgaris was made. However, hypopyon lesions were found to be an atypical feature.

Figure 1

(a) “Half-half” blisters on the limb. (b) Multiple vesicles and erosions on the abdomen. Half-half blister can also be seen

Figure 2

(a) Tzanck smear showing acantholytic cells magnification [×40]. (b) H and E, stained images showing intraepidermal cleft in pemphigus [×100]. (c) DIF showing “Fish net appearance” in the epidermis magnification [×100]

Pemphigus vulgaris is a chronic epidermal immunobullous disease, clinically characterized by fragile, flaccid blisters that develop on normal or erythematous skin or mucosa, and rapidly rupture, leaving painful, crusted erosions. The presence of acantholytic cells on Tzanck smear, suprabasal acantholysis on histopatholgy and intercellular IgG deposition on immumnofluorescence study confirm the disorder, as in our case.[1] The most striking feature in our case was the formation of hypopyon in the form of blisters filled half with clear fluid and half with pus, which are predictive of subcorneal pustular dermatosis (Sneddon–Wilkinson disease), another immunobullous relapsing subcorneal pustular eruption characterized by the presence of predominant flexural lesions, sterile pustules, negative Nikolsky's sign, intercellular IgA deposits in the upper epidermis.[23] Hypopyon formation is seen classically in bullous impetigo and staphylococcal scalded skin syndrome, where exotoxin produced by Staphylococcus aureus results in loss of cohesion between keratinocytes by cleavage of Dsg1. However, this was not present in our patient. Albeit both pemphigus vulgaris and bullous pemphigoid with multiple pustules has been reported in the past, to the best of our knowledge this is the first reported case of pemphigus vulgaris with half-half blisters,[456] that merits future study.

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