Track: Clinical Studies

Abstract:

Grover disease (GD) is an acquired, pruritic eruption that commonly affects the trunk. Acantholysis is a hallmark histologic feature of GD, with multiple histopathologic subtypes having been described. It has recently been observed that some patients with GD may improve with dupilumab, suggesting a role for Th2 immunity in its pathogenesis. Thus, markers of dupilumab-responsiveness in GD are of increasing interest. In this retrospective study, we evaluated whether the degree of eosinophils and/or spongiosis, findings implying Th2 polarization, varied across histologic subtypes of GD. We also explored whether such patterns were conserved in patients with multiple biopsies. We reviewed 198 cases of GD diagnosed between 2023 and 2025. The primary histologic subtype, presence of eosinophils, spongiosis, neutrophils, solar elastosis, perivascular inflammation, papillary dermal edema, and acanthosis were graded. Histologic subtypes included pemphigus vulgaris-like (32.3%), Darier-like (29.3%), spongiotic-acantholytic (19.2%), epidermal dysmaturation predominant (11.6%), Hailey-Hailey-like (3.6%), pemphigus foliaceous-like (2.5%), and bullous pemphigoid-like (1.5%). Eosinophils were present in 114 cases (57.6%) and did not differ significantly across subtypes (p=0.29). Significant spongiosis was present in 70 cases (35.4%) and was, as expected, significantly increased in the spongiotic-acantholytic subtype (p<0.0001). Among patients with two biopsies from different anatomic sites (n=23), eosinophil and spongiosis scores were conserved in 63% and 71% of biopsy pairs, respectively. Our findings suggest that Th2 activation in GD is common, and that reporting the presence or absence of eosinophils and spongiosis may be helpful for clinicians. Future studies evaluating whether these features correlate with dupilumab response are needed.