Special Stains and Immunohistochemical Stains in Hair Pathology

The document from May 2016 reviewed the role of special stains and immunohistochemical (IHC) stains in diagnosing hair disorders, based on 65 relevant articles. The authors concluded that there is no evidence to support the routine use of any specific stain or panel of stains in hair pathology, as no stain can reliably distinguish between nonscarring and early scarring alopecia, and most IHC stains are used primarily in experimental settings. They noted that certain stains have limited diagnostic utility, such as PAS being negative in kerion and elastic stains being useful only in late-stage scarring alopecia. Some stains, like those for mucin, may help differentiate between lupus erythematosus and lichen planopilaris, and lymphocytic markers may be useful in diagnosing lymphoma-associated alopecia. Despite these findings, the practical application is limited, and these stains are not part of routine diagnostic protocols. The document also discusses the role of various stains and markers in understanding the pathology of different types of alopecia and the changes in the dermis, but ultimately suggests that special and IHC stains are not routinely necessary in hair pathology, with the exception of antifungal stains for suspected tinea capitis.