title: Eosinophil-rich syphilis: a report of four cases.
abstract: The differential diagnosis for eosinophil-rich skin lesions often includes a drug reaction, allergic contact dermatitis and rarely, response to a helminth infection. However, many unrelated entities, such as infections, neoplasms and inflammatory dermatoses, can have a prominent eosinophilic infiltrate. Syphilis is classically associated with plasma cells, but other patterns of inflammation have been reported, including ulcerative, granulomatous and eosinophil-rich. Classic teaching might indicate that the presence of eosinophils argues against a diagnosis of syphilis. We present four cases of secondary syphilis with increased eosinophils, ranging from 8 to >200 eosinophils per 10 high-power fields (×400 magnification). Patient 1 had lesions on the penis and scrotum, with greater than 200 eosinophils per 10 high-power fields. Patient 2 had lesions on the back, with 150 eosinophils per 10 high-power fields. Patient 3 had lesions on the bilateral arms, with 8 eosinophils per 10 high-power fields. Patient 4 had lesions involving the anus, with 17 eosinophils per 10 high-power fields. These cases highlight that the presence of an eosinophil-rich infiltrate on skin biopsy should not exclude syphilis from the differential diagnosis.
authors.affiliation: Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Rosa
authors.affiliation: Department of Dermatology, University of Wisconsin, Madison, WI, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Bennett
authors.affiliation: Sections of the Departments of Dermatology and Anatomic Pathology, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Melissa P
authors.initials: MP
authors.lastname: Piliang
mesh_terms: D000328:Adult; D001706:Biopsy; D003937:Diagnosis, Differential; D004802:Eosinophilia / Q000382:microbiology* / Q000473:pathology; D004804:Eosinophils / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012871:Skin Diseases / Q000097:blood / Q000382:microbiology* / Q000473:pathology; D013587:Syphilis / Q000097:blood / Q000188:drug therapy / Q000382:microbiology / Q000473:pathology*; D014210:Treponema pallidum / Q000302:isolation & purification
keywords: dermatopathology; histopathology; pathology; skin