Seasonal variation of transient acantholytic dyskeratosis (Grover's disease)

Background: Grover's disease (GD), or transient acantholytic dermatosis, is a pruritic, papulovesicular eruption characterized histopathologically by acantholysis with or without dyskeratosis. The origin of GD is unknown. Suggested causes include sweating, heat, immobilization occlusion, external beam and ultraviolet radiation, and xerosis. GD has also been found to occur in association with other diseases. Objective: Our aim was to assess whether GD exhibits seasonal variation and, if so, to determine whether any inferences can be drawn from its seasonal variation regarding its cause. Methods: We identified 385 patients who fulfilled both clinical and histopathologic criteria for GD among 423,106 patients diagnosed at the Ackerman Academy of Dermatopathology in New York City during the period from July 1, 1999 through June 30, 2004. By design, no hospitalized patients were studied. Results: A diagnosis of GD was given to 0.09% of biopsy specimens at the Ackerman Academy of Dermatopathology. GD was diagnosed approximately 4 times more commonly in winter than in summer, although the number of biopsies was constant. The average age of GD patients was 64 years with a male/female ratio of 1.95:1. The most common histopathologic type of GD was pemphigus vulgaris. GD was Suspected clinically in 54% of patients. Limitations. This study did not assess hospitalized patients with GD or GD patients who lived outside the northeastern United States. Because the data assessed resided in a commercial dermatopathology laboratory, patients assessed in almost all cases had insurance coverage. Patients without insurance likely were not included in the study. Conclusions. The diagnosis of GD constitutes a higher proportion of biopsies in the winter than in the summer and therefore, by inference, occurs more frequently in the winter. In the winter, elderly men whose skin is naturally xerotic sweat less and are exposed to low ambient humidity. Rather than being caused by sweating and heat, GD arises against a backdrop of an intact but xerotic epidermis with decreased sweat production and is likely related to impaired epidermal integrity.