Arthritis, in general terms, is inflammation and swelling of the cartilage and lining of the joints, generally accompanied by an increase in the fluid in the joints. Arthritis has multiple causes; just as a sore throat may have its origin in a variety of diseases, so joint inflammation and arthritis are associated with many different illnesses.

Arthritis is a frequent component of complex diseases that may involve more than 100 identifiable disorders. If the feet seem more susceptible to arthritis than other parts of the body, it is because each foot has 33 joints that can be afflicted and there is no way to avoid the pain of the tremendous weight-bearing load on the feet.

Arthritis is a disabling and occasionally crippling disease; it afflicts almost 40 million Americans. In some forms, it appears to have hereditary tendencies. While the prevalence of arthritis increases with age, all people from infancy to middle age are potential victims. People over 50 are most prone to arthritis.

Arthritic feet can result in loss of mobility and independence, but early diagnosis and proper medical care can help significantly.

Besides heredity, arthritic symptoms may arise in a number of ways:

• Through injuries, notably in athletes and industrial workers, especially if the injuries have been ignored (which injuries of the feet tend to be).

• Through bacterial and viral infections that strike the joints. The same organisms that are present in pneumonia, gonorrhea, staph infections, and Lyme disease cause the inflammations.

• In conjunction with bowel disorders such as colitis and ileitis, frequently resulting in arthritic conditions in the joints of the ankles and toes. Such inflammatory bowel diseases seem distant from arthritis, but treating them can relieve arthritic pain.

• Using drugs, both prescription drugs, and illegal street drugs, can induce arthritis.

• As part of a congenital autoimmune disease syndrome of undetermined origin. Recent research has suggested, for instance, that a defective gene may play a role in osteoarthritis.