Intraepidermal neutrophils--a clue to dermatophytosis?
BACKGROUND
Dermatophyte infections are occasionally diagnosed by histopathology. Spongiotic or psoriasiform features are typical but non-specific, and neutrophils may be present within the stratum corneum. Traditionally, this latter finding has been felt to be a diagnostic clue for dermatophytosis, and usually precipitates a periodic acid Schiff (PAS-D) stain to confirm the presence of hyphae in the stratum corneum. Our objective was to evaluate whether the presence of neutrophils within the stratum corneum is a sensitive or specific test for dermatophytosis.


METHODS
We performed a retrospective case-control study on 303 cases of spongiotic or psoriasiform dermatitides over a 35-month period. Hematoxylin and eosin (H&E) and PAS-D stains were utilized to identify intraepidermal neutrophils and fungi.


RESULTS
The sensitivity and specificity for diagnosing dermatophyte infection based upon neutrophils within the stratum corneum were 62 and 59%, respectively. The positive and negative predictive values in our population were 4 and 98%, respectively.


CONCLUSIONS
The histologic feature of neutrophils within the stratum corneum is neither sensitive nor specific in the diagnosis of dermatophytosis.
Meymandi
Simin
S
Division of Dermatology, University of British Columbia, Vancouver, Canada.
Silver
Shane G
SG
Crawford
Richard I
RI
D003881:Dermatomycoses / Q000473:pathology*; D006801:Humans; D025301:Hyphae / Q000166:cytology; D003904:Mitosporic Fungi / Q000472:pathogenicity / Q000502:physiology*; D020556:Neutrophil Infiltration; D009504:Neutrophils / Q000473:pathology*; D010503:Periodic Acid-Schiff Reaction; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity