Exploring the Significance of Eosinophil Infiltration in Diagnosis of Psoriasis: A Cross-sectional Analysis

Background & Objective: There is controversy whether eosinophils are involved in the pathogenesis of psoriasis. This study aims to assess the quantity of eosinophils in pathological specimens obtained from individuals diagnosed with psoriasis.

Methods: cross-sectional and retrospective study 91 skin samples were obtained from patients with diagnosis of psoriasis. Two experienced dermatologists thoroughly reviewed the specimens' demographic characteristics, clinical features, and pathological attributes. Subsequently, eosinophils were counted within all microscopic fields, utilizing a magnification of 200.

Results: Eosinophils were present in approximately 70.3% of the examined samples, with a mean eosinophil count of 2.42±0.63. Although no significant correlation was observed between the clinical subtype and the average eosinophil count, eosinophils were most commonly detected in the cases presenting generalized pustular psoriasis (100%) and vulgaris types (71.11%). Notably, patients exhibiting Munro's microabscess and dilated papillary dermal blood vessels exhibited a significantly higher number of eosinophils (=0.007 and =0.039, respectively). Additionally, a notable association was identified between presence of spongiosis, and eosinophil counts in the pathological samples (=0.04).

Conclusion: Presence of eosinophils may not contradict a diagnosis of psoriasis. Furthermore, a notable association may be observed between the number of eosinophils and presence of spongiosis, dilated dermal papillary vessels, and Munro's microabscess.