Alopecia in Rhesus Macaques Correlates with Immunophenotypic Alterations in Dermal Inflammatory Infiltrates Consistent with Hypersensitivity Etiology

The study examined the cause of alopecia in 36 Rhesus macaques and found evidence suggesting that it may be due to chronic hypersensitivity dermatitis, similar to atopic dermatitis in humans. The affected macaques showed skin pathology with increased numbers of CD4+ cells, histiocytes, and mast cells in the dermis, and the severity of inflammation correlated with the degree of hair loss. No significant abnormalities in blood chemistry, CBC profiles, serum cortisol, or IgE levels were found to explain the alopecia. The study also noted that macaques born outdoors or with lung mite infections had a lower incidence of alopecia, supporting the idea that reduced pathogen exposure may contribute to the development of dermatitis and subsequent hair loss. The findings imply that alopecia in these macaques could affect immune response studies and that future research should explore the immune dysregulation associated with the condition.