Ask anyone who has it: Rheumatoid arthritis (RA) is a devastating diagnosis to receive, as it is an autoimmune disease that can cause severe pain and joint deformity and also happens to be incurable. However, if there were ever a good time to be diagnosed with this incurable illness, it's now, as the treatment options available are the most advanced they have ever been—and they are allowing many people with RA who would have otherwise been destined for wheelchairs to live full and active lives.
One of the early signs of rheumatoid arthritis is stiffness, pain, and swelling in the hands and feet. The onset is gradual for some and immediate for others, but regardless, most people with RA wake up one day and realize that the joints in the ball or sole of their feet are too painful to walk on. At the same time, they might also notice their fingers stiffen while trying to open a jar, or that they can't bend certain finger joints while cooking because it's too painful. As the disease progresses, pain and stiffness may spread to the wrists, elbows, shoulders, knees, ankles, and hips.
Causes of Rheumatoid Arthritis
With RA, the immune system attacks the body's own joint tissues, resulting in inflammation, which can cause progressive damage to affected joints. Specifically, the immune system attacks the fluid within joints as well as the joint lining, known as the synovium. The synovium becomes acutely inflamed, causing a warm and swollen joint. Continued inflammation, especially if left untreated, eventually thickens the synovium and causes cartilage and bone to erode, which leads to joint deformity and decreased range of motion. In addition, the muscles, tendons, and ligaments that surround and stabilize the joints may become weak.
Many people experience periods of increased symptoms, referred to as flares, followed by less disease activity or even periods of remission, a state of no pain, stiffness, or swelling.
Parts of the Foot Affected by RA
When it comes to the feet, RA typically affects the metatarsophalangeal (MTP) joints of the toes. When RA persistently affects the MTP joints, a gradual outward (lateral) shift in the toes can occur. This may cause both feet to develop bunions (hallux valgus). RA may also cause shifting of the forefoot and loss of stability, which leads to toe contractures, such as hammertoes. Toe contractures and changes in toe joint flexibility will often lead to calluses and pain beneath the ball of the foot. All of these changes to a foot's structure and shape can make finding a comfortable shoe more difficult for an RA sufferer.
Other joints of the foot that can be affected by RA include the ankle joint and the talonavicular joint, which is part of the foot's arch. When the talonavicular joint is affected, the foot can become destabilized and flat feet (pes planus) can develop.
What distinguishes RA pain from the more common osteoarthritis (OA) pain is that multiple joints are usually affected at the same time with RA and the joint symptoms are generally symmetrical, occurring on both sides of the body equally. Another feature that distinguishes RA from OA is the tendency for RA to cause a longer period of morning stiffness. An RA sufferer will often experience stiffness in affected joints for one or more hours after awakening, compared with an OA sufferer, whose joint stiffness may diminish after a few minutes of stretching or motion in the morning.
Other Foot Problems Associated with RA
Heel pain. This is a common recurring problem for people with RA and can occur at the back of the heel or on the underside. Conditions associated with heel pain include plantar fasciitis (heel spur syndrome), Achilles tendonitis, and retrocalcaneal bursitis. Retrocalcaneal bursitis occurs when a fluid-filled sac (bursa) behind the heel bone becomes inflamed, causing pain and swelling.
Nerve entrapment syndromes. When RA inflames the joint lining, or synovium, the swelling can compress nerves and cause symptoms of a pinched nerve, also known as a nerve entrapment. One common nerve entrapment in the foot is called tarsal tunnel syndrome. Symptoms of tarsal tunnel syndrome include burning, tingling, or shooting pain in the area of the foot's arch and sole.
Rheumatoid nodules. A rheumatoid nodule appears as a lump beneath the skin, usually over a bony prominence or tendon. In the foot, a rheumatoid nodule may appear over the Achilles tendon or on the side of the big toe if a bunion (hallux valgus) is present.
Skin rashes. The inflammation associated with RA can affect small blood vessels, which in turn can cause certain skin manifestations, including rashes or wounds on the lower legs. Another skin finding associated with RA is splinter hemorrhages, which are small areas of broken blood vessels that are usually seen on the sides of fingernails or toenails.
While not everyone will have foot involvement with RA, the majority of people do have some level of it. However, the most important thing to note is that there are many pharmacological treatment options as well as lifestyle interventions that can make a tremendous difference in managing all aspects of the disease, including its foot manifestations. A close relationship with your rheumatologist—who will work to relieve your pain and inflammation, halt joint damage, and improve your sense of well-being—will ensure the best outcomes possible throughout the course of your disease.