What's causing my mother cat's mouth rash? How can I help her at home?

Hello, and thank you for your question. This rash could be related to a skin infection (bacterial or fungal), skin parasites such as mites, or allergies. I would start by removing any plastic dishes or plastic toys from her environment, as plastic is a common contact allergen in cats. You can also try wiping the chin area with hydrogen peroxide, which can help if this is a case of mild chin acne. I would place an e-collar (cone) on her head to prevent her from further damaging her chin as well. If there was a recent diet change just before the skin problem started, I would remove this and try a different diet (one for kittens, since she is still nursing).

If these tips do not help, I would recommend taking Mama to the vet. They may recommend a skin scraping or cytology to check for bacteria or mites. They can also prescribe antibiotics if an infection is suspected, or anti-itch medications if allergies are at play.

I hope this helps, and that Mama feels better soon!