title: The periodic acid-Schiff stain in diagnosing tinea: should it be used routinely in inflammatory skin diseases?
abstract: BACKGROUND
  The clinical presentation of tinea is usually, but not always, characteristic. The purpose of this study was to determine whether the routine use of the periodic acid-Schiff (PAS) stain in inflammatory skin disorders is requisite for identifying clinically undiagnosed tinea cases and to ascertain whether there are histopathologic clues that suggest the diagnosis of a dermatophyte infection.
  
  
  METHODS
  Hematoxylin and eosin (H&E)-stained slides from 60 PAS-positive tinea cases were examined histologically by two observers. One observer, aware of the diagnosis of tinea, searched for hyphal elements and also recorded in detail epidermal, dermal, and follicular changes. The second observer, not aware of the diagnosis beforehand, reviewed the same slides, together with randomly mixed slides from 21 non-tinea cases, recording the same parameters as the first reviewer.
  
  
  RESULTS
  Of the 60 cases of tinea, only 45% were diagnosed clinically. Histologic examination of H&E sections by the two observers disclosed the presence of hyphal elements in 68 and 45%, respectively. No significant histologic differences, except for the presence of hyphae, were observed between tinea and non-tinea cases.
  
  
  CONCLUSIONS
  The finding that only 57% of PAS-positive cases of tinea showed hyphal elements on H&E examination alone, together with no other differentiable histologic characteristics, lends strong support for the routine use of PAS-staining for inflammatory skin disorders.
authors.affiliation: Dermatopathology Section, Department of Dermatology, Boston University School of Medicine, Boston, MA 02118, USA.
authors.forename: Amina
authors.initials: A
authors.lastname: Al-Amiri
authors.forename: Vandana
authors.initials: V
authors.lastname: Chatrath
authors.forename: Jag
authors.initials: J
authors.lastname: Bhawan
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Stefanato
mesh_terms: D004396:Coloring Agents; D003872:Dermatitis / Q000473:pathology*; D003951:Diagnostic Errors; D003955:Diagnostic Tests, Routine; D004801:Eosine Yellowish-(YS); D005456:Fluorescent Dyes; D006416:Hematoxylin; D006801:Humans; D025301:Hyphae / Q000302:isolation & purification; D010503:Periodic Acid-Schiff Reaction; D016037:Single-Blind Method; D014005:Tinea / Q000382:microbiology / Q000473:pathology*
chemical_list: D004396:Coloring Agents; D005456:Fluorescent Dyes; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin