Histiocytoma, also known as histiocytosis or fibrous histiocytoma, is a benign skin tumor that commonly occurs in dogs. It is caused by an accumulation of histiocytes, a type of white blood cell, in the skin. Histiocytomas typically appear as raised, hairless bumps on the skin that range in size from a pea to a golf ball. While histiocytomas are benign and rarely spread to other areas of the body, they can sometimes ulcerate or become infected, so it is often recommended to have them removed. Here is a look at the common ways vets recommend getting rid of histiocytomas in dogs.
Observe and Wait
One of the most common recommendations for treating histiocytomas is to simply observe the growth and wait for it to go away on its own. This is because the vast majority of histiocytomas are self-limiting and will spontaneously regress within 2-3 months. During this time, you can monitor the histiocytoma and make sure it does not become irritated, ulcerated or infected, as that may require medical treatment. However, in most cases, the body’s immune system will recognize the histiocytoma as foreign and attack it, causing it to eventually disappear without any intervention.
Steroid Injections
If a histiocytoma is in a location that is prone to trauma or ulceration, vets may recommend injecting steroids directly into the tumor to speed up its regression. The most commonly used steroid is triamcinolone acetonide. The injections help reduce inflammation and irritation associated with the histiocytoma, which helps shrink it faster. Most histiocytomas will significantly shrink within 1-2 weeks after steroid injections and resolve entirely within 4-6 weeks.
Cryosurgery
Cryosurgery, also known as cryotherapy, uses extreme cold to destroy abnormal tissue. To remove a histiocytoma with cryosurgery, the vet will apply liquid nitrogen directly to the tumor. This causes the cells within the histiocytoma to freeze and die. The dead tissue then separates from the healthy skin and sloughs off. This is an effective way to get rid of a histiocytoma quickly, usually with minimal scarring. Redness, swelling and minor blistering of the skin are common immediately after treatment but typically resolve within a few weeks.
Surgical Removal
If a histiocytoma is large, in a high-risk location, or persists longer than expected, a vet may recommend surgical removal. This involves putting the dog under anesthesia and surgically cutting out the tumor. The skin is then sutured closed. This provides immediate and complete removal.However, surgery is more invasive and costly than other options. It also poses a small risk of infection, scarring and other postoperative complications. For these reasons, surgery may be reserved for problematic histiocytomas that do not respond to more conservative treatments.
Topical Creams
Some vets may prescribe topical creams or ointments to help remove a histiocytoma. Imiquimod is an immune-boosting cream that can stimulate the body’s immune system to attack the tumor. Capsaicin creams made from chili peppers may also help reduce the size and irritation of a histiocytoma when applied regularly. However, topical medications usually take longer to work than other treatments and may not fully eliminate the growth.
Radiation Therapy
Radiation is sometimes used to treat aggressive or rapidly growing histiocytomas that have not responded to other therapies. By damaging the DNA of tumor cells, radiation can help shrink and eliminate the unwanted growth. However, this option requires multiple visits for radiation sessions and sedation or anesthesia during each treatment. It also comes with a higher cost compared to more conservative options. For these reasons, radiation is typically reserved for the most problematic cases.
Home Remedies
While medical treatment is recommended for the best results, some people try home remedies to remove histiocytomas. However, there is limited evidence that these DIY options are effective. Some things people have tried include:
- Apple cider vinegar – Applying a diluted ACV solution to the histiocytoma several times per day
- Tea tree oil – Applying diluted tea tree oil, which has anti-inflammatory effects
- Garlic – Rubbing raw garlic on the histiocytoma daily
- Colloidal silver – Applying this liquid, which has antimicrobial properties
While these may help reduce irritation, inflammation, or secondary infection, they are unlikely to fully eliminate a histiocytoma on their own in most cases.
When to See the Vet
It is always a good idea to have your veterinarian assess any new lumps or bumps on your dog to ensure it is a benign histiocytoma and not another type of tumor. Vets can also provide guidance on the best treatment options based on factors like the tumor’s location, size, and your dog’s health and comfort. You should schedule an appointment right away if you notice any of the following warning signs:
- The histiocytoma continues to grow rapidly
- Signs of infection like pus, worsening swelling, redness, or heat
- Bleeding, ulceration, or scratching/irritation of the tumor
- Loss of hair around the histiocytoma
- Additional lumps developing elsewhere
- Signs of pain or discomfort in your dog
With early veterinary care, most histiocytomas can be successfully treated or safely left alone to regress on their own. However, it is important to monitor the tumor closely and follow up with your vet if you have any concerns about changes in its appearance, size, or symptoms it may be causing.
Risk Factors
While any dog can develop a histiocytoma, certain factors increase the risk:
| Risk Factor | Description |
|---|---|
| Age | Most common in young dogs under 3 years old |
| Breed | Some breeds like Boxers, Boston Terriers, Bulldogs, Schnauzers, and Shar Peis are prone to histiocytomas |
| Genetics | Family lines with a history of histiocytomas are at higher risk |
| Immune system function | Dogs with weakened immune systems may struggle to fight off histiocytomas |
| Sun exposure | Prolonged sun exposure may be linked to histiocytoma development in some dogs |
| Allergies | Chronic allergic reactions may play a role in histiocytoma formation in some cases |
Prevention
While most histiocytomas appear randomly and cannot be prevented, there are some steps owners can take to potentially lower their dog’s chances of developing one:
- Avoid excessive sun exposure – Use dog-safe sunscreen and limit time outside during peak hours
- Feed a healthy diet – Nutrient deficiencies may impact immune function
- Prevent obesity – Excess weight can impair the immune system
- Control allergies – Reducing allergic reactions may help prevent some histiocytomas
- Boost immunity – Discuss supplements that support immune health with your vet
- Check skin regularly – Identify growths early for easiest treatment
- Consider pet insurance – Policies can offset costs if treatment is needed
While we can take steps to try to reduce risk, histiocytomas ultimately tend to develop randomly. Staying alert for any new lumps and bumps and seeking prompt veterinary care offers your dog the best protection and outcomes.
Conclusion
Histiocytomas are common benign tumors in dogs that form due to an accumulation of histiocytes in the skin. While they mostly affect young dogs under age 3, they can develop in pets of any age. These firm, rounded growths usually appear suddenly and can occur anywhere on the body. The good news is that the vast majority of histiocytomas will disappear on their own within a few months without treatment. However, it is still important to have all new lumps or bumps checked by your vet to ensure they are benign. For histiocytomas that areproblematic due to their location, size, or irritation, several treatment options are available, including steroid injections, cryosurgery, surgical removal and radiation. Home remedies may also be tried, but typically do not fully eliminate the tumors. With appropriate monitoring and treatment when needed, most dogs recover fully from these common skin tumors.
