The common cause of a painful bump on the back of the heel is called Hagland's deformity. This is due to an enlarged bony prominence on the back of the heel. It can involve the entire back of the heel or just a portion of the back of the heel, usually on the outside portion of the heel. Also called the Pump Bump, it is most common in women and is frequently a result of pressure from the back of the shoe. As the shoe rubs on the back of the heel bone it begins to swell and enlarge. Quite often a bursa will form. A bursa is a sack that is created over any bony prominence when excessive pressure or friction to the areas occurs. Bursae can be filled with a thick watery like fluid.
Treatment consists of removing the pressure and avoiding shoes that rub on the back of the heel. Orthotics, custom molded shoe inserts, can be useful because they reduce the rocking motion side-to-side of the heel while walking which aggravates the painful area. Cortisone injections can temporarily reduce the pain or eliminate the pain. Surgery can be the treatment of choice if other means to reduce the pressure are unsuccessful.
Spurring in the Achilles tendon
Closely related to Hagland's deformity is an enlargement that can occur on the back of the heel that is a result of the formation of a large spur where the Achilles tendon attaches. Treatment is the same as with the Hagland's deformity except that the surgical procedure to remove the spurring is more complex and has a longer recovery period.
Swelling and lumps can also occur in the Achilles tendon just above its attachment into the heel bone. Termed Achilles tendonitis, this occurs when there is a tear in the tendon. If this goes untreated the tendon is at risk of rupturing. Treatment consists of immobilization with a cast, possibly crutches to take weight off the foot, oral anti-inflammatory drugs and if severe surgery may be necessary. Once the area is healed aggressive physical therapy and calf muscle stretching exercises may be needed. There is another small tendon that attaches in the back of the heel that can become injured. It is called the Plantaris tendon. This tendon can tear or rupture during exercise. It is associated with a sudden onset of pain during exercise and mimics Achilles tendonitis.
An Uncommon Cause - Xanthomas
An uncommon cause of small lumps in the Achilles tendon is an excessively high cholesterol level in the blood stream. This is a hereditary disorder that results in the deposition of cholesterol in the Achilles tendon. This is a serious condition and requires aggressive treatment by a physician to lower the cholesterol levels. Left untreated the high cholesterol levels can lead to premature heart attack and death.