I have a 1 and a half year old female Syrian hamster and have noticed today that she has bitten off a patch of fur near one of her legs. She has bitten so much that the skin is showing there. She must have done it overnight last night as the bald patch wasn't there last night.

She is eating as normal and moving around as normal. She lives alone and has a large sized cage with plenty of areas to hide and explore. We haven't changed her food or bedding recently although she has started to sleep in the same area where she urinates.

Does anyone have experience of a hamster doing similar? Could it be mites?

I have a hamster who had this, in fact her fur has just finished growing back from it. It is unlikely she has mites because these would generally cause baldness all over, usually around the face and ears, not just in one spot and your hamster would be scratching a lot. Where near her leg is the patch? Is the skin smooth and unbroken but reddish in colour? As you say she has started sleeping in the same area she is peeing in, I'm leaning towards her having urine scald. The Uric acid causes burning of the fur and skin if it has prolonged contact with it, which will create sore bald patches, especially in an animal unable to get away from the source or one that is overweight and can't keep itself clean. These patches are usually found at the top of the back legs and around the tail, but they'll occur anywhere if the hamster has had that part of itself in direct contact for a long time. If she has this she hasn't pulled the fur out, the acid has 'burnt' it.

To treat it you need to remove the cause to give the new fur time to grow back. Mine was caused by the style of wheel I had which was easy to deal with as I just took it out and replaced it, but yours isn't that straightforward as it's the cage bedding itself. Firstly, try to scoop out any wet bedding straight away, as if it's not there she can't lie on it. Then you could either try to retrain her into using somewhere else, by throughly cleaning the cage in white vinegar to remove any scent, then putting some of the wet bedding in the place you do want her to go, which they normally latch on to quite quickly, or stop her using that area completely by putting a heavy toy or object over it. She might give up if she couldn't get to the spot, but even if she does still pee there, she won't be able to lie on it.

If you want to be certain she hasn't got mites or lice you can get a spot on from the vet for small animals called Xeno 50 Mini that you can use as a precaution. If you do get this, ask your vet to work out the right dose as the ones on the box are not easy to follow and fatally overdosing such a small animal is easily done.

Other common causes of bald patches are boredom, a hamster with not enough to occupy it or too small a cage can and will over groom and pull its fur out through boredom, and females can have a bald underneath from pulling the fur for nest lining, but neither of these fit in with your hamster's description.

Thank you very much for your detailed reply.

I did think it may be Urine scald but have not experience of this with a hamster before so good to hear from someone who has knowledge of this.

She does have a hamster toilet but didn't take to it but will try her with it again. I will also try your ideas about retraining her to urinate in a different area and will get some white vinegar pronto.

Thank you again for taking the time to reply.

Your very welcome, hope it helps you. Once you have stopped the problem, you should start seeing new fur growth fairly quickly usually, but mine took almost two weeks to see any hair so it varies. If she starts going patchy elsewhere I would pop her to the vets for a parasite check, or if it doesn't start clearing up after you have removed her. Don't be tempted to put any cream on the patch, she'll only lick it off and if she starts bothering the area she may well make it worse and sore. Hope she's back to normal soon!

Hi there,

Here's what I've done with all my hamsters:

Line the bottom of the cage with thick newspaper. Don't use sawdust etc. because that can cause skin and eye problems. Provide a mix of bedding material - a mix of shredded newspaper, toilet paper, bits of wool, fabric, commercial stuff, etc.. and she'll make a nice nest for herself.

Wherever she normally pees, you can put her toilet. I use a coffee jar with a flat side.. You need to put something she has already peed on in there so she'll smell it and go there to pee. Each day, remove the jar, rinse it out and replace it. The smell will linger.. If you're not going to empty the jar every day, line it with something absorbent.

Every week, remove 1/4 or 1/3 of her bedding and supply new stuff, so her bedding is gradually being refreshed. At the same time, take a peek at her food stores and take away any fresh food, as it will turn everything mouldy. If you let the hamster organise her environment, she'll keep it very clean and orderly. Don't disturb the cage more than that otherwise she'll get confused and pee all over the place. It's really stressful for hamsters to have their cages completely turned out, and it's unnecessary. If you find that she's storing her droppings in a pile somewhere, you could remove those when you do her cage. If you organise the cage like that your work will be minimal.

Even with an interesting environment, hamsters need a lot of stimulation, so keep adding new things for her to explore and enjoy.. Cardboard egg boxes with holes in them, extra ladders, sprigs of lavender and other scented harmless plants, etc.. Also, give her some nice fresh food each day - a variety of wee pieces of greens, celery, red pepper - just a variety of little pieces so she'll eat them all and not store them.. You can also hang up millet seed sprays and other bird treats so she'll have to climb up to get them.

If you live alone, you can hand-tame your hamster, hamster-proof the home and let your hamster out to run around for an hour or two every night. (They're nocturnal so they sleep until late in the evening). (You have to put all electrical flexes out of their reach, as they might chew them, and seal every tiny crack in skirting boards, under doors, etc. Hamsters can almost flatten themselves and get through spaces of less than 1cm.) Supervise them carefully when you first let them out, so you can pinpoint potential hazards. Leave the cage on the floor so she'll be able to climb back in when she feels like it. I've done this with all my hamsters. Over time, once I knew the hamsters were safe, I'd keep the cage on the bedroom floor, and open it when I went to bed.. I'd go to sleep with the hamster running around the room, then when I awoke, the hamster would be tucked back up in its bed, and I'd close the cage. One time I awoke with the hamster running up my leg under the duvet during the night.. hehehe.

If the cage is managed the way I described above, with a happy hamster keeping the house in order, they're happy to go back into their cage and won't try to make a nest anywhere else. If they don't go back into the cage themselves, then close the cage door so they cannot go in and out to help themselves to food, then when they're hungry put some nice smelling cheese and peanuts into the cage and they'll soon hop back in and you can shut the cage door.

You always take a slight risk in letting your little pet run loose, but if you are careful they have a far happier life and I think that the risk's worth taking. Same as when you let your cat run loose outside or let the dog off the lead.