The Dreaded Lump: Causes, Treatment, and Care in Pet Rats

Pet rats are super prone to lumps and bumps. They have fast metabolisms, so tumors can sometimes appear suddenly and grow just as quickly. As a species, rats are genetically predisposed to developing tumors, but there are some other common causes of lumps too.

If you notice that your pet rat has a lump, your best bet is to take them to the vet as soon as possible. Most lumps need medical treatment, and the earlier you catch them, the better chances your rat has of recovering.

If you give your pet rats lots of massages and snuggles, you’ll probably notice lumps pretty early on.

Causes of lumps in pet rats

Pet rats can develop lumps for a few different reasons. Some are easier to treat than others, but most require vet care before the lump gets too big. Here are some potential causes:

Most common causes

1. Mammary tumors: Female rats are especially prone to developing mammary tumors. Rats have extensive mammary tissue, covering most of their belly and wrapping up around the sides. Tumors can even be found under the armpits or into the groin. These tumors often move around with the skin. Male rats can develop mammary tumors too, but it’s less common than with the ladies. Mammary tumors need to be surgically removed by a vet before they grow too large. They often come back again, so your vet might suggest spaying at the same time the tumor is removed to prevent future ones.
2. Other tumors: Both cancerous and non-cancerous tumors are common in pet rats. Regardless of whether they’re cancerous, tumors can grow quickly and become so large that they cause mobility issues, or even cut off your rat’s blood supply. Your vet can help you decide whether surgery will help your rat, depending on how old your rat is, as well as the type and location of the tumor.
3. Abscesses: These are swollen pockets of pus that develop when bacteria gets into a small cut or wound. Abscesses often look the same as a tumor for a few weeks – just like a round bump. But then they develop a dark patch or scab that will come to a head. (You may or may not be able to see the dark patch under your rat’s fur.) Abscesses often pop up overnight and grow larger within a couple of days. They will often form around a nip or bite from another rat. If your rat has an abscess, you can sometimes get it to drain and go down by itself by soaking it with a warm, wet wash cloth several times a day. (Squeezing abscesses is not recommended because you don’t want to force the infection deeper into their body.) Once the abscess drains – just a heads up, very gross! – just keep an eye on it to make sure it’s healing properly and not building up again. If it wont drain on its own, your vet might recommend a course of antibiotics to help clear the infection.

Less common causes

1. Cysts: Cysts are fluid-filled sacs that can form under the skin. In comparison to abscesses, they’re often harder, forming more of a scab. They’re more common (or easier to see) in hairless rats and males, who produce more oils. Rats can get sebaceous cysts that look a bit like pimples or blackheads, and you can squeeze them to drain them if they get too big (I know, ewwww!) Cysts are usually harmless. Small cysts that aren’t causing any issues may not require treatment, but you’ll have to watch them to make sure they don’t grow or become infected.
2. Inflammation or skin infections: Sometimes, lumps in pet rats can be a result of inflammation or skin infections, such as dermatitis. You might notice that your rat seems to be itchy or scratches itself too much. Treatment for inflammation or skin infections typically involves topical medications, such as antiseptic creams or ointments, to soothe the affected area and promote healing. Your veterinarian may also recommend changes in bedding or environmental factors to prevent further irritations.
3. Warts, moles, etc. Rats can also get warts and odd skin growths, similar to the ones you see on people! They seem to grow most often on their tails, but they can happen anywhere on the body. Again, these don’t typically cause any problems for rats, but definitely look strange. If in doubt, get your vet to take a look and make sure it’s not a tumor or skin infection.

What to do when you find a lump

Lumps in pet rats almost always need vet care, as they may need surgical removal, medication or antibiotics. It’s important to see your vet as soon as possible, because lumps can grow large pretty fast in pet rats. It also becomes riskier to operate on rats as they age, so the sooner your rat receives treatment the better. Early detection gives your ratties the best chances of recovery.

Treatments for lumps

Depending on the cause of the lump, your vet might recommend a few different treatment options:

1. Antibiotics or medication: If the lump is an abscess caused by a bacterial infection, your vet may prescribe antibiotics or topical medication to help clear the infection. Make sure to administer the medication as directed and complete the full course to ensure the infection is properly treated. Stopping antibiotics too early can cause the infection to come back with a vengeance!
2. Surgical Removal: In some cases, surgical removal of the lump might be needed, especially if it’s causing discomfort, growing quickly, or interfering with your rat’s quality of life. Your vet will discuss the risks and benefits of surgery with you. Usually, you will need to separate your rat from the others and monitor them closely for a couple of days after the surgery. Rats have a bad habit of licking, scratching or even biting at the stitches when they get itchy, and will sometimes re-open the wound without your supervision. To keep rats from barbering their incision, you can try cutting the toes off of a sock and using it as a little sweater!
3. Palliative Care: Surgery can be risky for older rats, and is sometimes not possible, as with tumors around their face. Your vet can speak with you about whether they think it makes sense to risk anesthesia or not. For elderly rats, your vet might just recommend medication to manage the pain. Some tumors grow slowly enough that they don’t impede your rat’s quality of life too much as it ages. You can monitor your rat each day to make sure they’re still happy and comfortable.

Conclusion

It can be disheartening to find a lump on one of your ratties. Unfortunately, they come with the territory of keeping pet rats, so you’ll probably notice one at some point. With vet care and treatment, often your rats can still live out their full life span in comfort. I wish you and your little buddies the best of luck!