Eosinophils in psoriasis: A systematic review and meta-analysis introducing a study quality assessment tool for diagnostic pathology studies.

Eosinophils were found in approximately half of systematically studied and published cases of psoriasis. When present, their quantity is variable, with the likelihood of having greater than 5 eosinophils in a biopsy section comparable to having between 1 and 5. Greater than 5 eosinophils, as an isolated finding, would not be typical of psoriasis, but should not preclude its diagnosis without considering the overall histologic context.