Case Study: chronic cellulitis in equine hindlimb

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DATE: April 30th, 2019 
VETERINARIAN: Ann-Marie Hancock, DVM
CASE DESCRIPTION: Chronic cellulitis in equine hindlimb
PATIENT INFORMATION: Cassie – 14 year old grey warmblood mare


Transdermal CO2 was used as a primary and adjunctive treatment for a chronic recurrent cellulitis of the left hind limb. Cassie began to develop bouts of cellulitis about 2 years ago in the left hind leg. The first bout occurred soon after receiving vaccines. Multiple bouts occurred, usually after vaccines, medications, osteopathic work, or a stressful event. They were treated using antibiotics (Baytril), steroids and diuretics. The bouts began to occur more regularly, about every two months and were costing at least $1000 for treatment each time. Transdermal CO2 made a significant difference and there have been no further occurrences of cellulitis. The recovery from the cellulitis was dramatic and the horse is performing better and without recurrence of injury. Hoof wall integrity and growth improved. The owner is appreciating a financial benefit as well. 


In the fall of 2017, Cassie suffered her first episode of cellulitis of the left hind limb. She had been unsuccessfully treated for scratches on the same limb for at least one year prior to first episode. Treatment was started immediately after swelling was discovered. She was febrile with a hot swollen left hindlimb. She was given NSAIDs, antibiotics (Baytril), diuretics, steroids and the limb was wrapped using a compression bandage between twice daily hydrotherapy. These episodes occurred regularly over the following fourteen months and were treated the same each time.

Each episode presented with fever greater than 101’F, severe edema to the Left Hind from the hock distal to the hoof. Palpation revealed-reduced pulse in left hind, hard soft tissue and weeping of interstitial fluid.

Further bouts of cellulitis occurred on a regular basis, about every two months, starting with a low grade fever and then the leg would blow up, be treated with antibiotics, NSAIDs, wrapping etc and start to go down, but never get completely better. The circumference of the leg post treatment failed to return to a pre-episodic measurement. Pitting edema remained as did the skin lesions. Her owner started leaving the left hind leg in a compression wrap any time she was not outside, and then eventually left the wrap on all the time to prevent further swelling. 

In January 2019, Cassie presented for a regular exam and we discussed the chronic nature of the cellulitis. It had gotten to the point where she would begin to swell up any time the wrap was removed and any change to her routine could set off a bout of cellulitis. She had started to develop a fever of 101 degrees the day before and we thought she was on the verge of having another bout of cellulitis.


Cassie was started on Ceftiofur twice daily for one week. We continued bandaging and started treatment with transdermal CO2 with the sleeve placed up to the hock and sealed with Vetrap®. CO2 was added to the bag through the valve and allowed to sit for 20 minutes.

The carbon dioxide treatment was applied daily for 1 week. Treatment was continued every 48 hours for 2 more weeks, then every 3 days for another 3 weeks. 


Cassie spiked a fever once on the second day of treatment and has maintained a normal temperature under 100.5 and usually under 100.0 after that day. She seemed to relax during her treatments and walk more comfortably afterwards. Skin temperature began to decrease following treatment by the 4th day of CO2 therapy. Edema decreased significantly by 4th day of CO2 therapy. Cassie also had some skin lesions similar to scratches that were recurrent and non-responsive to multiple topical therapies. These began to go away by the 4th day of CO2 therapy. 

By the second week of carbon dioxide therapy, Cassie had marked improvement in skin quality and definition in the hind limb. By the end of the month, her leg looked normal, with minimal skin lesions.

Therapy has been discontinued for 2 months at this time. The leg looks completely normal – good definition in the tendons and ligaments and no skin lesions. She has not had any further bouts of cellulitis. Vaccines and osteopathic manipulation have been performed in that period of time and no adverse cellulitis was seen following either event. 


Transdermal CO2 played an important role in healing this horse’s leg and improved the speed with which she healed as well as the duration of positive outcome following therapy. The swelling and pain associated with the suspected cellulitis began to resolve by day 4, with the edema reduced by the 7th day. Cellulitis can be very difficult to treat in many cases. The result here was significantly faster and of longer duration than expected. 

As far as hoof wall integrity and health, the overall hoof wall growth increased on the treated limb compared to the untreated limb. The hoof wall thickness increased by 1 mm on the treated limb versus the untreated hind limb. 


Transdermal CO2 treatment proved beneficial to the rapid recovery and continued lack of recurrence of cellulitis in this horse. The treatment was simple, non-invasive and painless. It can be done easily on any horse that can be confined to a stall or small grooming area. The rapid improvement, as well as the sustained improved health of Cassie’s leg, has been amazing and can be attributed to the use of the Airjector CO2 device. The potential for its use in field situations where the owner can aid in administering therapy with affected patients was well demonstrated by the use in this case. I will use the Airjectorvet CO2 therapy for my future lymphangitis and cellulitis cases.

Veterinary Transdermal