The Striking Appearance of a Rare Skin Condition: “Half-Half” Blisters (Subcorneal Pustular Dermatosis)

The rest of the laboratory workup, including complete blood cell count with differential, complete blood cell count, thyroid-stimulating hormone, and serum protein electrophoresis, did not reveal a cause for the symptoms. Desmocollins are structural proteins necessary for cell-to-cell adhesion.4-7 This are distinct from the desmoglein proteins targeted in other pemphigus variants, for example, pemphigus vulgaris (desmoglein 3 and 1) and pemphigus foliaceus (desmoglein 1).8 When these proteins are targeted, the structural framework linking skin cells together breaks down and vesicles or bullae are formed. Because desmocollin 1 is located in the stratum corneum of the skin, loss of function results in small superficial vesicles and pustules that desquamate.8 In most cases, SPD presentation is confined to the skin. [...]SPD can be associated with other cutaneous and systemic conditions, such as Raynaud phenomenon, Sjögren syndrome, systemic lupus erythematosus, and neutrophilic dermatoses (eg, pyoderma gangrenosum and Sweet syndrome), paraproteinemias (predominantly IgA monoclonal gammopathies [monoclonal gammopathy of undetermined significance]), and multiple myeloma.