Fatigue has many possible causes, which can range from a lack of sleep to a health issue such as thyroid disease. When fatigue is long-term, severe, and it can?t be explained by lifestyle or a medical condition, the cause could be a condition called chronic fatigue syndrome.

Doctors don?t yet know what causes chronic fatigue syndrome. They think it might stem from an infection, a problem with the immune system, body-wide stress, or a combination of factors.

The primary chronic fatigue symptoms include fatigue that?s unexplained and severe enough to interfere with everyday activities. The exhaustion doesn?t improve with rest, and it often gets worse with activity. Other chronic fatigue syndrome symptoms include difficulty remembering and concentrating, pain in the muscles or joints, headaches, tender lymph nodes in the armpit or neck, and a sore throat. These are the most typical chronic fatigue syndrome symptoms, but many people with the condition complain of other ailments. Depression, chills, night sweats, dizziness, fainting, food sensitivities, and bowel problems have all been associated with chronic fatigue syndrome.

The variety of possible chronic fatigue syndrome symptoms can make the condition difficult for doctors to diagnose. No blood test or imaging scan is specifically designed to pick up chronic fatigue syndrome. People are diagnosed only after they?ve had symptoms for six months or longer, other conditions have been ruled out through testing, and they meet a set of specific chronic fatigue symptom criteria.

Chronic fatigue syndrome can be as difficult to treat as it is to diagnose. Patients will often work with a team of specialists, which includes a primary care physician, mental health specialists, and physical therapists to manage symptoms and learn how to cope with the condition.