Trichomycosis Pubis Workup

Updated: Jun 16, 2022
  • Author: Jeannette Rachel Jakus, MD, MBA; Chief Editor: Dirk M Elston, MD  more...
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Approach Considerations

The diagnosis of trichomycosis is made clinically; however, other diagnostic modalities may be used for doubtful cases. [18] Wood lamp examination reveals a pale, yellowish fluorescence; however, it is important to note that this does not occur in cases caused by Serratia species. [2] A new diagnostic method includes ultraviolet light–enhanced visualization (ULEV). [8] in which high-contrast maps of epidermal desquamation are obtained and variations in light reflections recorded by a camera provide information on an altered stratum corneum. [19] Using the ULEV method can highlight the presence of the corynebacteria (white) in addition to the surrounding biofilm enveloping the hair shaft. Several reports note dermatoscopic findings of cottony structures around the hair, [2, 10, 15] which have also been described as transparent crystalline “rosaries of crystalline stones.”

Culture or API Coryne system (a standardized system for identification of coryneform bacteria in 24 hours) are the criterion standard diagnostic tests. [2] Hair culture can be used to grow the anaerobic diphtheroids present as short gram-positive rods. These studies usually are not essential but may be used if no response to initial treatment occurs or targeted antibacterial treatment fails to result in a cure (and fungal superinfection should be eliminated).

A study by Lacarrubba et al suggests that trichoscopy may be helpful in the diagnosis of trichobacteriosis. [20]


Histologic Findings

While usually not performed, in rare cases samples of hair have been removed and sent for pathology slide preparation. Upon periodic acid-Schiff (PAS) staining, a dense sheath surrounding the hair shaft is present. [5] The bacteria are extrafollicular, affecting only the cuticle without penetrating the cortex or marrow of the hair, as further demonstrated by electron microscopy studies. [10] Two other distinctive pleomorphic Corynebacterium species can encapsulate the hair. These three bacterial species are entrapped in a background of cementitious biofilm elaborated by the bacteria, which possibly serves as a mechanism for host immune evasion. [8] Superinfection with cocci or fungi also can be present.