TLDR  Alopecia areata is an autoimmune disease causing hair loss, treatable with immune-modulating drugs, and linked to genetics.   
  Alopecia areata (AA) was identified as an autoimmune disease characterized by nonscarring hair loss, often associated with other autoimmune conditions. The presence of autoreactive T lymphocytes supported its autoimmune etiology, with both CD4+ and CD8+ T cells playing roles in its pathogenesis. Studies showed that AA could be transferred to human scalp explants on SCID mice using T lymphocytes, indicating a T cell-mediated mechanism. Immune modulating drugs, such as corticosteroids, were beneficial in managing AA. Genetic predisposition was suggested by associations with certain HLA alleles, and AA was observed to have a protective effect against Type I diabetes. Animal models were used to study AA's pathophysiology and test therapies. Neuropeptides and altered cutaneous innervation were implicated, with a pilot study using capsaicin cream showing vellus hair regrowth. The document emphasized the need for further research into treatments and genetic studies.
            13 citations
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  December 2001   in “Dermatologic therapy”
           13 citations
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  December 2001   in “Dermatologic therapy”    Alopecia areata causes varying hair loss patterns, affecting hair, nails, and possibly glands, with treatment outcomes depending on disease duration and extent.  
      19 citations
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  December 2001   in “Dermatologic Therapy”
           19 citations
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  December 2001   in “Dermatologic Therapy”    Horizontal scalp biopsy sections are better for diagnosing alopecia areata, showing fewer hair follicles and more miniaturized hairs.  
      16 citations
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  December 2001   in “Dermatologic Therapy”
           16 citations
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  December 2001   in “Dermatologic Therapy”    Alopecia areata has a complex genetic basis that was not fully understood as of 2001.  
      36 citations
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  October 1996   in “Dermatologic Clinics”
           36 citations
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  October 1996   in “Dermatologic Clinics”    Mice are useful for researching human hair loss and testing treatments, despite some differences between species.  
               178 citations
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  June 1994   in “Journal of Investigative Dermatology”    Alopecia areata in these mice is inherited, more common in young females, and can be treated with triamcinolone acetonide.  
    
  
        
      6 citations
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  March 2019   in “JAAD case reports”
           6 citations
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  March 2019   in “JAAD case reports”    A new mix of anthralin and calcipotriene might help treat severe hair loss.  
      148 citations
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  December 2018   in “Journal of autoimmunity”
           148 citations
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  December 2018   in “Journal of autoimmunity”    Alopecia areata is an autoimmune disease causing patchy hair loss, often with other autoimmune disorders, but its exact causes are unknown.  
      4 citations
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  November 2018   in “JAAD case reports”
           4 citations
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  November 2018   in “JAAD case reports”    Alopecia areata can sometimes appear as a straight line of hair loss instead of round patches.  
               May 2018   in “Journal of cosmetology & trichology”    Combining platelet-rich plasma therapy with prostaglandin-F eye drops can significantly regrow hair in alopecia universalis.