Noninflammatory hypotrichosis in white-tailed deer and raccoons in the eastern United States

Noninflammatory hypotrichosis includes a spectrum of disorders with 2 phenotypes: follicular or ectodermal dysplasia. Here, we describe 6 follicular dysplasia cases in 2 wild adult male raccoons (Procyon lotor) and 4 wild yearling or adult white-tailed deer (Odocoileus virginianus), and 1 case of ectodermal dysplasia in a captive-reared stillborn male white-tailed deer, all from the eastern United States. All cases had regional or body-wide hairlessness. Skin hyperpigmentation was observed in those with follicular dysplasia. The stillborn fawn also had multiple developmental defects, including craniofacial dysplasia and unilateral anophthalmia. Histologic features of affected skin were heterogeneous. Follicles were typically normal in number and distribution, but their stage of development varied (primitive, anagen, telogen, kenogen, or a combination thereof). Hair shafts were either formed, poorly differentiated, or absent. Sebaceous glands were variably hypoplastic, normal, or hyperplastic. We did not definitively determine an underlying etiology; however, a genetic cause is suspected.