The Foot and Rheumatoid Arthritis
Rheumatoid arthritis (RA) is the commonest type of inflammatory arthritis. Up to 90% of people with this condition will report associated foot problems. For some people, the foot is the first area of the body to present with signs and symptoms of RA. For others, it may be months, years or they may never experience any foot problems at all.
Musculoskeletal signs and symptoms in the feet:
Signs and symptoms of rheumatoid arthritis that you may experience in your feet can vary from soreness, warmth and swelling (a flare) of one or more foot joints that lasts a few days or longer, through to joint erosions, with joint instability, pain and associated changing foot shape. It should be stressed that with the advent of improved and earlier drug therapy, the ‘classic’ changes to foot shape as a result of RA, should become less common. However, if you experience any new foot pain, changes in joint shape, nodules, swelling or inflammation you should seek urgent attention from your rheumatology Health Care practitioner, (Rheumatology Specialist Nurse, Podiatrist, GP or Consultant).
The joints which are most commonly affected in RA are: the smaller joints of the toes, the ‘metatarsophalangeal (MP) joints’ in the forefoot, the ‘subtalar’ joint and less commonly, the ankle joint.
The diagram below shows where the main joints of the feet are shown in the diagram below:
Symptoms of joint pain and swelling can impact on a person’s ability to undertake their usual daily activities and it is recommended that exercise should be reduced when you are experiencing the signs and symptoms of an acute ‘flare’. Treatment aimed at reducing painful symptoms, supporting the joints of the feet and improving foot function is usually via the use of appropriate insoles or orthoses and it has been found that the early use of orthoses, together with successful medical management, can slow the development of joint changes.
RA can cause bursae; (fluid filled sacs) that develop as a result of excess rubbing in a particular area that can become inflamed (bursitis) and painful. Bursa can often be found under the ball of the foot affected by RA. Treatment for this type of bursa usually involves reducing pressure over the ball of the foot with the use of insoles or orthoses.
The photograph on the right shows the appearance of bursa across the balls of the feet.
In some people with RA, nodules may form in the soft tissues that may be susceptible to rubbing from hosiery and footwear. Common sites for these nodules in the feet are:
- over the Achilles tendon
- in the heel pad and
- over any bony prominences.
The photograph on the left shows the appearance of nodules.
Skin and Nail problems:
Shape changes in the front of the foot and the toes can create pressure sites that develop corns and calluses (hard skin). These may develop into areas of ulceration if not treated appropriately, and so it is advisable to request podiatry guidance if hard skin or corns are present on your feet. Professional guidance should always be sought with regard to self-treatment of hard skin and corns - you are advised not to use pedicure blades, corn plasters and paints on these areas. The reason for not using these is that they can remove good skin and cause breaks in the skin which bacteria can then invade and cause a serious infection.
The photograph on the right shows a hard corn (left picture) and callus (right picture) on the ball of the foot.
Circulation and nerve problems in the lower limb:
Some people with RA can experience decreased blood supply to feet and legs associated with atherosclerosis (hardening of the arteries) which can lead to cramp-like pains in your calf, thigh or buttock muscles when walking and other circulation related disorders such as Raynaud’s phenomena where the small blood vessels in the skin of the hands and feet ‘shut down’ in response to changes in temperature leading to the following colour changes: toes/fingers go white, then blue and then red. These colour changes may also be accompanied by a tingling sensation in the affected areas. In rare cases people with RA can develop a skin rash, that may ulcerate, known as ‘vasculitis’ - an inflammation of the blood vessels. This is usually associated with long term disease and the risks of it occurring are increased by smoking.
Some people may experience problems with the nerve supply to their feet known as Peripheral Neuropathy (this can be caused by vasculitis as the small blood vessels that feed the nerves can be damaged, thus leading to abnormal nerve function). This may mean that they cannot feel pain or other sensations such as temperature (hot or cold) and pressure, or they may experience ‘pins and needles’ in certain parts of their feet as a result of a trapped nerve.
The above are types of problems that are less common and hopefully you may never experience them, but you should be aware of the symptoms if they arise and inform your rheumatology Health Care Practitioner responsible for monitoring your rheumatoid arthritis.