My hamster has lost fur in one large patch on his side. Noticed around 10 days ago. No other noticeable changes in health or behaviour.

最佳回答：

Thanks for reaching out about Cashew and including photos. Patchy hair loss can be due to self grooming, external parasites (mites are microscopic), fungal or bacterial dermatitis, endocrine disorders and others. A veterinary visit is recommended to assess and provide a diagnostic/treatment plan. Each diagnosis requires a different treatment.
Good luck.