Looked fine in the morning, but by afternoon a patch was bald; the kitten is in heat, no wound, just slight redness from scratching. The vet said maybe allergy. What’s going on and how do I handle it?

Hair loss and itching on the back of a cat’s neck can be caused by parasite bites, allergies, or fungal or bacterial skin disease. Photos alone can’t directly determine the cause, so it’s best to take the cat to a veterinary clinic for a skin scraping test to identify the exact source of infection before using targeted medication. Also, if the cat scratches the area often, put an E-collar on it (make sure the collar doesn’t rub the spot). Finally, keep the environment clean and deworm your cat regularly to reduce pathogen exposure.