A lupus band test is a skin test done on a sample of skin biopsy. The method of testing used for this is direct immunofluorescence staining. Lupus basically denotes a group of skin disorders in which there are characteristically eroded lesions on the skin.
There are several types of lupus lesions on the skin, some of which are listed below:
Chilblain lupus erythematosus is a condition which is caused due to a microvascular injury induced by cold. Though this kind of injury initially appears like chilblains, it eventually begins to become discoid lupus erythematosus. Another form of lupus erythematosus is cutaneous lupus erythematosus which involves only the skin. If the direct immunofluorescence staining turns out to be positive, and with that, deposits complementing immunoglobulins are found at the dermal and epidermal junctions, it means that there is presence of a lupus band.
This particular test can help distinguish lupus bands from lupus erythematosus and cutaneous lupus. A systemic lupus test is usually positive for that part of the skin that has the lesions and the part that does not have the lesions. In case of cutaneous lupus, however, the test is positive only on the skin that has it.
If the skin on the face of the patient is affected by systemic lupus, there may be several skin abnormalities. There may be discoid lupus - butterfly rashes also known as malar erythema and acute subcutaneous lupus. A biopsy of the skin may be obtained to monitor changes in the skin. These changes may be particularly characteristic of the lupus band in several patients. The symptoms of lupus may not always be evident. Many of the criteria could be absent, and therefore, to get a medical diagnosis, a lupus band test becomes absolutely necessary.
The biopsy results usually highlight areas of the skin which are inflamed due to bands of lesions. There may be different levels of inflammation present in different layers of the skin. There could be special tests such as antibody staining that need to be done.
These tests are performed after a few weeks of the immunofluoroscent tests. In such tests, if there is presence of lupus bands, antibodies can be seen deposited at the junctions of the epidermis and dermis. When viewed under a microscope, there is a fluorescent line which shows a lupus band.
In 90% of the patients, the test results are positive. There may be an association of the test results with exposure to the sun.