Alopecia Areata is an autoimmune disease. It usually occurs alone, by itself, but may be a manifestation of Lupus (SLE). It presents as one or more patches of complete baldness surrounded by normal hair (pictures below). If we look carefully we might see some “exclamation point hairs,” for which the shaft near the skin is narrower than the growing tip. These can pluck out easily, confirming the diagnosis. Sometimes there are also fingernail and toenail changes.
To rule out SLE, we inquire about other possible SLE symptoms, and order blood tests for Antinuclear Antibodies (ANA). We also order a Rapid Plasma Reagin (RPR) blood test, for Syphilis, which can also cause similar type of hair loss. The problem, however, is that a positive RPR might mean patchy hair loss due to 2° Syphilis, but might be a false-positive, which commonly occurs with SLE.
A “confirmatory test” is done routinely with the RPR to distinguish between Syphilis and a false-positive. However, if a person ever had syphilis treated in the past, the “confirmatory” will remain positive forever from that one episode. False-positives RPR values (titers) are usually low (≤1:8); with 2° Syphilis they’re usually lots higher, but it could be hard to distinguish (see link for stages of Syphilis). Other causes of a false-positive RPR include HIV, pregnancy, and other autoimmune diseases.
We treat Alopecia Areata by injecting the area with steroids. If it’s due to SLE (suspect if a very high ANA), we’d want a Rheumatologist to manage full treatment. Focal hair loss can rarely advance to Alopecia Totalis (complete baldness), or more rarely even Alopecia Universalis (loss of all body hair).