Clinicopathologic Overlap of Vulvar Psoriasis and Candidiasis.

Objectives: The study's aim is to assess if vulvar psoriasis and candidiasis may be distinguished by clinical presentation and histopathologic appearance.

Methods: The pathology database identified biopsies with corneal or subcorneal neutrophils, acanthosis, and dermal lymphocytic infiltrate. Exclusions were age younger than 18 years and unavailable or uninterpretable slides. Clinical data included demographics, comorbid conditions, symptoms, examination, microbiology, treatment, and response. Histopathologic review documented site, thickness, and characteristics of stratum corneum and epidermis, distribution of neutrophils, and infiltrate. Cases were stratified by microbiologic presence or absence of Candida albicans.

Results: Biopsies from 62 women with median age of 60 years were associated with C. albicans on vulvovaginal culture in 28 (45%), whereas 26 (42%) were negative, and 8 (13%) lacked microbiologic assessment. Swab-positive women were more likely to have diabetes, receive prereferral estrogen, and report vulvar pain. Specialist clinical impression was candidiasis in 33 (53%), psoriasis in 11 (18%), comorbid candidiasis and psoriasis in 7 (11%), dermatitis in 10 (16%), and unknown in 2 (3%). Visible fungal organisms occurred in 16 (26%) cases and were associated with diabetes and satellite lesions. Other than presence of organisms, there were no histopathologic differences stratified by microbiologic result.

Conclusions: The histopathologic triad of corneal/subcorneal neutrophils, acanthosis, and dermal lymphocytic infiltrate is common to vulvar psoriasis and candidiasis, and clinical features do not reliably distinguish between them. Microbiologic assessment and single-agent treatment are useful strategies to clarify the diagnosis.