Background Lodderomyces elongisporus is a yeast with a worldwide distribution that has been reported as a cause of infection in immunocompromised humans and in a dog that had been quilled by a porcupine. Objectives The objective of this report is to describe the clinical presentation, diagnosis and treatment of dermatitis caused by L. elongisporus in a North American porcupine (Erethizon dorsatum). Animal One wild adult male North American porcupine from New York state, USA. Methods and materials The porcupine was presented for alopecia and scaling dermatitis over the caudal dorsum. Diagnostic testing included cytological evaluation, trichogram, bacterial and fungal culture, and histopathological examination of skin biopsies. Results Histopathological findings from skin specimens demonstrated mild eosinophilic perivascular‐to‐interstitial dermatitis with superficial dermal fibrosis, mild epidermal hyperplasia with moderate‐to‐marked intracorneal and intrafollicular yeast. Fungal culture with matrix‐assisted laser desorption/ionization confirmed L. elongisporus as the cause of the dermatitis. The porcupine was treated with a six week course of oral itraconazole with clinical resolution. Clinical relevance Infection with L. elongisporus should be included as a differential diagnosis for North American porcupines exhibiting signs of dermatitis including scaling and alopecia. This case report may be relevant for the diagnosis and treatment of porcupines with dermatitis and for animals or humans that have been quilled by a porcupine.