Bursitis is defined as an inflammatory condition involving the bursae, which are scattered pads of tissue that act as shock absorbers and cushions over the body’s bony prominences. Some bursae, also called bursal sacs, are found in the same place in everyone, such as in the elbow, shoulder, hip, and behind the Achilles tendon. Others appear as a result of excessive external pressure and internal bone irritation.
In the foot, bursitis can commonly develop in one of four areas. The most common location is under the heel. Some cases of heel pain are due fully or partially to inflammation of the bursa that sits under the heel bone (calcaneus). Another common area is behind the Achilles tendon, and inflammation of this bursa has a role in many cases of Achilles tendonitis. A third location is found on the outer side of the big toe joint, usually in association with a bunion deformity. As the bone becomes prominent over the years along the side of the foot, shoe irritation can stimulate the development of a protective bursa, which in turn can become inflamed. Finally, a similar bursa can develop on the outer side of the foot near the base of the big toe, where a Tailor’s bunion forms (bunionette).
There are many other areas a bursa can develop in the foot and become inflamed, but these are generally less common or tend to contribute in smaller ways to an overall inflammatory condition. For example, bursae can develop in between the long bones of the feet, but their role in pain is limited compared with other inflammatory conditions found there, such as inflammation of the joint capsules at the base of the toes, or nerve inflammation.
Treatment of bursitis centers around reducing inflammation and controlling mechanical irritation on the body. Anti-inflammatory medications, icing, and corticosteroid (cortisone-like) injections are the mainstays of inflammation reduction. The reduction of mechanical irritation involves the use of padding, wider shoes, specialized inserts to control foot structure, or surgery to reduce or correct the prominent bone or deformity.