In discoid lupus, only the skin is involved. The skin rash in discoid lupus often is found on the face and scalp. It usually is red and may have raised borders. Discoid lupus rashes are usually painless and do not itch, but scarring can cause permanent hair loss. Over time, 5 to 10% of patients with discoid lupus may develop SLE.

Patients with SLE can develop different combinations of symptoms and organ involvement. Common complaints and symptoms include fatigue, low-grade fever, loss of appetite, muscle aches, arthritis, ulcers of the mouth and nose, facial rash ("butterfly rash"), unusual sensitivity to sunlight (photosensitivity), inflammation of the lining that surrounds the lung (pleuritis) and the heart (pericarditis), and poor circulation to the fingers and toes with cold exposure

More serious organ involvement with inflammation occurs in the brain, liver, and kidney. White blood cells and blood clotting factors also can be decreased in SLE, thereby increasing the risk of infection and bleeding.

Over half of the patients with SLE develop a characteristic red, flat facial rash over the bridge of their nose. Because of its shape, it is frequently referred to as the "butterfly rash" of SLE. The rash is painless and does not itch. The facial rash, along with inflammation in other organs, can be precipitated or worsened by exposure to sunlight, a condition called photosensitivity. This photosensitivity can be accompanied by worsening of inflammation throughout the body, called a "flare" of disease.

Most patients with SLE will develop arthritis during the course of their illness. Arthritis in SLE commonly involves swelling, pain, stiffness, and even deformity of the small joints of the hands, wrists, and feet. Sometimes, the arthritis of SLE can mimic that of rheumatoid arthritis (another autoimmune disease).

Inflammation of muscles (myositis) can cause muscle pain and weakness.

Inflammation of blood vessels, (vasculitis) that supply oxygen to tissues, can cause isolated injury to a nerve, the skin, or an internal organ. The blood vessels are composed of arteries that pass oxygen-rich blood to the tissues of the body and veins which return oxygen-depleted blood from the tissues to the lungs. Vasculitis is characterized by inflammation with damage to the walls of various blood vessels. The damage blocks the circulation of blood through the vessels and can cause injury to the tissues that the vessels supply.

Inflammation of the lining of the lungs (pleuritis) and of the heart (pericarditis) can cause sharp chest pain. The chest pain is aggravated by coughing, deep breathing, and certain changes in body position. The heart muscle itself rarely can become inflamed (carditis). It has also been shown that young women with SLE have a significantly increased risk of heart attacks from coronary artery disease.

Kidney inflammation in SLE can cause leakage of protein into the urine, fluid retention, high blood pressure, and even kidney failure With kidney failure, machines are needed to cleanse the blood of accumulated poisons in a process called dialysis.

Involvement of the brain can cause personality changes, thought disorders (psychosis), seizures, and even coma. Damage to nerves can cause numbness, tingling, and weakness of the involved body parts or extremities. Brain involvement is called cerebritis.

Many patients with SLE experience hair loss (alopecia). Often, this occurs simultaneously with an increase in the activity of their disease.

Some patients with SLE have Raynaud's phenomenon In these patients, the blood supply to the fingers and toes becomes interrupted upon exposeure to cold, causing blanching, bluish discoloration, and pain in the exposed fingers and toes.