If your hamster is scratching itself repeatedly, then some of the most likely reasons include dry skin, mange, mites or some form of allergic reaction.
If your hamster’s ears are very dry and flaky, then this could just be a little bit of a dry skin issue, just as many humans get. This can be solved by smoothing a little bit of petroleum jelly on the back of their ears once per day. This should be enough to provide some relief to your hamster, and to keep the skin nice and hydrated.
Another cause of scratching is mange. Sarcoptic mange is caused by mites, and they cause lots of dry, irritated skin that is quite scabby and crusted. The mites are microscopic, but although they're invsible to the human eye, they’re causing your pet a lot of discomfort and pain, as they burrow under your hamster’s skin. It’s important to your pet’s health that this condition is treated quickly, as it’s very painful.
Healthy hamsters are free of skin afflictions and won't scratch themselves much
If your pet has dry, irritated skin all over its body, then the diagnosis could be non-mange mites. Mites are tiny little invertebrates that live on your pet’s skin. In small numbers, this variety are not a problem, but in larger numbers they can be extremely uncomfortable for your pet. The skin on your hamster will be quite crusty, and they may be suffering from some hair loss. This can be treated by some medication given to you by a vet.
Another option is that your hamster is allergic to something in its cage. If you hamster has a poor reaction to something, then this could be the cause of the itching. Allergies are dangerous if not treated or addressed. If the scratching is accompanied by anything like wheezing, sneezing, laboured breathing, or discharge from the nose or eyes, then the problem scratching could be caused by an allergy.
Don’t forget that your pet can be suffering from multiple health problems at once. For example, if they’re scratching as well as having a runny nose and trouble breathing, then they could be suffering from a respiratory infection and a mite infestation at the same time. If you can’t figure out why your pet is scratching itself so much, then a vet will usually be able to provide you with a diagnosis.