My cat has a rough red scab on the back of its neck — is it ringworm, and how should I treat it?

From the photo, the fur around the scab is sparse and follicle growth is suppressed; the owner should recall whether the cat was scalded or burned by a topical dewormer. If so, the scab is very likely caused by that, and you can disinfect with iodine and use a pet-specific follicle-repair medication. If not, it may be symptoms of parasitic, bacterial, or fungal infection.

When a cat is bitten by parasites such as fleas and the skin itches, red papules appear, so regular external deworming is recommended for prevention. In addition, if you suspect the red skin is ringworm, at home you can use a Wood’s lamp; if the affected follicle shows an apple-green glow, it can be preliminarily judged as ringworm, and an antifungal ointment such as compound ketoconazole can be applied.