It is not uncommon to see horses swell with subcutaneous edema. It happens most frequently in the hind legs and resolves when the horse begins exercising again.
Alternatively, swelling can be a bacterial infection and indicate a different condition with several potential causes. Regardless of the exact cause, the swelling will be extreme, hot and very painful to the touch, and the horse will be depressed due to the fever and discomfort. Lymphangitis, also known as vasculitis, big leg disease, staph infection or cellulitis and can occur with a simple cut or puncture that allows bacteria inside.
Source: AAEP, Facebook, November 23, 2021. Facebook Link. AAEP website Link.
In an acute episode, aggressive antibiotics and anti-inflammatories are a must. The most challenging part of treatment is getting the extremely painful horse to move to help get fluids to travel back up the leg.
Affected limbs might never return to normal, with the swelling causing long-term lameness. Recurrent bouts are common.” – Kennon Keckler, DVM
INSIGHTS: The fat leg poster on Facebook is nicely done and worthy of social media posts and links in newsletters. Horse owners busy with holiday activities might not be attuned to checking their horses closely and could miss swelling in legs.