Alopecia Areata in Aging C3H/HeJ Mice

Alopecia areata in C3H/HeJ mice, resembling human alopecia areata, was characterized by non-scarring hair loss with mononuclear cell infiltration around anagen follicles, primarily involving CD8+ and CD4+ T cells. Triamcinolone acetonide injections reduced the infiltrate and promoted hair regrowth. The disease appeared to be inherited and polygenic, with a higher incidence in females at younger ages. The incidence in a production colony was 0.25% for females and 0.035% for males, but selective breeding increased it to nearly 20%. In an aging colony bred for inflammatory bowel disease, the incidence was 4.7% for mice over 18 months, suggesting it might be a common aging change in this strain. This model could be valuable for studying human alopecia areata subtypes.