Discoid lupus must be just like “regular” lupus, right? I mean, lupus is lupus, no? You’d think so, but like most things within Rheumatology, it rarely makes that much sense. When one speaks of “lupus” they are usually talking about SLE or Systemic Lupus Erythematosus. SLE is a systemic (affects the entire body), autoimmune condition. Discoid Lupus, or DLE, is a condition solely of the skin. One can certainly have “discoid lesions” when they have SLE and we are always on alert for the development of SLE, but rest assured, they are two different entities.
The name “discoid” stems from the description of the typical rash seen with DLE: a disc shaped, red patch with a scale and with scaring. It is common to worry about “progression to SLE.” Thankfully, development of SLE is the exception, rather than the rule. Although dermatologists are often the main caregivers of DLE, a full evaluation by a rheumatologist can provide insight and peace of mind.
The Who, What & Why of Discoid Lupus
DLE is most common in women in their 30’s and 40’s. Similar to SLE, black women carry a higher risk (4x) for DLE compared to white. And black women are more likely to have a severe case at a younger age. DLE is a chronic, cutaneous (skin) condition that results in disc-shaped, red, “lesions” on the skin. These can be of varying size, but can get large. As the lesion expands, the skin in the center becomes lighter (hypopigmented) and thinner (atrophied; both of which are permanent changes. If these lesions occur in areas with hair growth, permanent hair loss can result. Most have “localized” DLE. This is defined as lesions limited to the head and neck. When lesions are located below the neck, DLE is “disseminated.”
A dermatologist’s physical exam will be enough to make a DLE diagnosis for many. In some cases, a skin biopsy may be necessary. Most with DLE will not have any other symptoms outside of their skin and will be diagnosed and managed solely by dermatologists. Why DLE develops is still as much of a mystery as it is with SLE. Cigarette smoke, exposure to certain viruses and UV light have been implicated, but we are still far from finding a definitive cause (and it is likely different for different people).
The Issue of Progression
The majority of those with DLE will NOT develop SLE. The risk is highest in the 1st 10 years after a DLE diagnosis, and even more so in the first 5 years. It is not uncommon for those with DLE to have a +ANA blood test. This makes the mere presence of a +ANA unhelpful. There is, however, some evidence that a very high ANA result suggests a higher risk for developing SLE.
I will always advocate for those with DLE to get the once-over by a Rheumatologist. (I’m biased) Dermatologists are amazing and usually have more experience treating the skin lesions of DLE. Rheumatologists can complement this care by using their expertise to identify any concerning systemic signs or symptoms. Because SLE in those with DLE isn’t common, most will get the once-over, told all is good, and can move on with confidence.
Treatment options for DLE
As you can imagine, early diagnosis, treatment and prevention is key. Developing good habits to limit UV light with SPF and protective clothing prevents new lesions. Dermatologists offer various treatment options taking into account the the lesion’s location, growth and size. With the use of creams, ointments or intra-lesional steroid injections, dermatologists can limit the spread of DLE lesions. Some will need oral or systemic treatment and in those cases dermatologists may seek out the help of rheumatologists. Rheumatologists usually have more experience managing the oral medications needed, such as hydroxychloroquine, methotrexate or azathioprine.