Diagnosing Cutaneous Lupus

Cutaneous lupus is a chronic skin condition in which rashes or sores appear on the face, scalp, chest, arms, and other sun-exposed parts of the body. It is an autoimmune disorder, which means that symptoms develop because the body’s immune system mistakenly attacks healthy skin cells. The condition can be a sign of systemic lupus erythematosus, also an autoimmune disease, which causes inflammation in joints and other parts of the body. 

To diagnose cutaneous lupus, an NYU Langone dermatologist examines your skin and may remove a small skin sample in a procedure called a biopsy. If your symptoms suggest systemic lupus, your dermatologist may recommend a blood test to confirm or rule out the diagnosis. 

Medical History and Physical Exam

In order to put your symptoms into context, a dermatologist may ask when you first noticed a rash or sore, how frequently the symptoms appear, and whether your skin feels warm, itchy, or painful. He or she also wants to know if the symptoms worsen after you’ve been in the sun. The doctor also asks whether anyone in your family has systemic lupus or cutaneous lupus, or whether you are experiencing any other symptoms—for example, joint aches or pains.

Your dermatologist closely examines your skin to determine the type, pattern, and shape of rashes or sores. He or she may then perform testing before making a diagnosis.

Biopsy

A dermatologist may need more information to confirm that you have cutaneous lupus rather than another skin condition, such as rosacea or psoriasis, which cause similar symptoms. He or she may perform a skin biopsy by removing a small piece of affected skin and sending it to a laboratory for testing. 

There are two common ways your doctor may perform a biopsy. One technique involves shaving off a small piece of skin with a scalpel, called a shave biopsy. In another method, known as a punch biopsy, the doctor uses a handheld device that resembles a pencil to punch through several layers of skin.

A biopsy takes place in your doctor’s office. He or she may use a local anesthetic to reduce any discomfort. Test results are usually available within two weeks.

Blood Test

If you have signs or symptoms of systemic lupus erythematosus, such as a butterfly rash on the face or persistent joint pain, your dermatologist may recommend a blood test to help determine if you have the condition. He or she draws blood and sends it to a laboratory. The test results usually arrive in five to seven days, and your doctor then discusses the results. 

If your dermatologist suspects systemic lupus, he or she can refer you to an NYU Langone rheumatologist, a doctor who specializes in inflammatory conditions, for additional tests and treatment.