What causes a hairless, scab-like patch under my bunny's chin?

Unfortunately the link with the picture seems not working properly. Generally speaking a bacterial or mite infection of the skin could be responsible for the signs you are noticing. Less commonly fungal infection can cause that. Please post again the link to the picture or a more specific description to receive further answers.

Hello! This picture does look suspicious for vent disease or possibly ringworm. Vent disease is usually treated with Penicillin, but it doesn't look like it's gotten any better. It may not cured because of using too low of a dose, which can lead to antibiotic resistance and a more difficult infection to treat. This may require that a different antibiotic or a higher dose of the same one is used. If the infection is ringworm, which is another round skin lesion that commonly affects rabbit's faces and is contagious, it will only respond to anti-fungal medication, so antibiotics will not be useful. Ringworm can spread to people as well, but is fairly easily treated. Sometimes, skin mites can cause small lesions of baldness like this. We generally use puppy/kitten Revolution (flea product that also treats mites) on rabbits when we are suspicious of this. It is a very safe product, so an easy treatment to try. I would recommend a vet visit to be totally sure of what you're treating and what doses to use. I think that will get them the quickest recovery. I don't know of any fatal diseases in rabbits that present like this, so rest easy! I hope you find this helpful! Thanks for using Petco Pet Education Center, formerly Petcoach!

Thank you for using Petco Pet Education Center, formerly Petcoach! I can see the areas you described, they appear somewhat red and crusty with hair loss. This can be caused by overgrooming (can be from lack of enrichment), a skin infection (bacterial or fungal), and certain skin mites. I recommend gently clipping the fur with an electric clipper to keep it clean and improve your ability to monitor it. You can also apply some silver sulfadiazene (SSD) ointment to the area. If there is no improvement over several days, then your bunny should be seen by a vet to determine the cause. I would also separate her from any other rabbits she may be housed with as fungal infections and skin mites are contagious. I hope this helps!

Thanks for reaching out about Cinnabun and including a photo. The crust on the nose and ears could be mites, and that could cause the skin to be dry also. Having a veterinarian examine him could help rule in/out other possible causes including bacterial. Good luck.

Thanks for reaching out about Bob and including photos. This does appear to be an infection, which could be bacterial, fungal or yeast. Did the veterinarian look into the mouth with an instrument (ototoscope) to visual cheek teeth? Moist dermatitis can be green with a bacterial infection called Pseudomonas, which can be difficult to treat. Try to train and switch to a water bottle. Maybe decrease vegetables. A new veterinary visit is recommended. Good luck.

I am sorry Takun is not feeling well. Most of the time these type of abscess are due to infected teeth. Most of the time this will not resolve unless the abnormal teeth are removed or the cause of the abscess is removed. I would recommend taking Takun to a vet who works on rabbit teeth for another exam and possible anesthesia with x-rays and tooth removal if needed. Hope that helps

This presentation could be due to a trauma or localized spot of skin infection (likely to be caused by bacteria but mites and fungal infections are possible as well). A check up, appropriate disinfection and possibly antibiotics (oral, topical or in a shampoo formulation) are needed to solve the problem. Disinfection may be started at home with very diluted hibiscrub or betadine or salted water baths. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further.