Novel peeling skin condition in neonatal Pacific walruses, Saint Lawrence Island, Alaska, USA.

We describe here a novel peeling skin condition (PSC) in 2 neonatal Pacific walruses ( subsp. ). Macroscopically, calves had various degrees of peeling skin exacerbated by mechanical trauma. Lesions occurred in areas subject to friction: ventrum, fore- and hindflippers, and associated joints. Histopathologic features included pseudocarcinomatous epithelial hyperplasia with orthokeratotic hyperkeratosis. Bacterial cocci were present within the stratum corneum. A few intraepidermal clefts were present. Inflammation, epidermolysis, and vasculopathies were not observed. PCR assays were negative for vesivirus and for exfoliative and toxic shock syndrome toxins. Tissue samples were cultured and bacteria isolated and identified by MALDI-TOF MS as , , , , spp., , and . Given the young age of the calves and their clinical presentation, congenital ichthyosis was suspected. No genetic differences were detected for sequenced portions of keratin genes (keratin gene ) between diseased and normal walrus skin. This rare PSC in neonatal Pacific walruses is recognized as novel by indigenous Alaskan marine mammal hunters of the Bering Strait region. A comprehensive diagnostic work-up of future case materials is needed to characterize the underlying biochemical defect(s).