Lupus erythematosus (LE) is a collection of autoimmune diseases that is a result of immune system hyperactivity and consequent destruction of normal, healthy tissues. LE has a wide spectrum of effects on the body and targets various organ systems such as the skin, heart, lungs, kidneys and joints.
The condition is fairly difficult to diagnose, largely owing to its mimicry of other diseases with similar symptoms. There are four main types of LE and these are; systemic lupus erythematosus (SLE), lupus erythematosus induced by drugs (DILE), discoid lupus erythematosus (DLE) and neonatal lupus erythematosus (NLE).
Systemic Lupus Erythematosus
SLE is the most common and serious form of the four LE types. The etiology of SLE is not entirely understood. However, there are several predisposing factors that may contribute to the pathogenesis.
While there is no exact gene implicated in SLE, there is believed to be a genetic component, since persons with SLE tend to have family members with other autoimmune disorders.
Moreover, there is a higher prevalence in women than in men and symptoms in women tend to worsen during menstruation and pregnancy. Hence, the female hormone estrogen is suspected to have some functional role in the condition.
In addition to genetics, sex and hormones, environmental factors also play a role. Triggers associated with SLE that may increase the risk of developing the disease include:
- Ultraviolet rays
- Silica dust
- Cigarette smoking
SLE manifests at any age with peak incidence being between the first and fifth decades of life. Furthermore, race is yet another predisposing factor and African Americans and Asians are more likely to be affected than any other group. However, this racial predisposition seems to be synergistic with environmental influences, because there is a contrast between low reported rates of SLE in black women in Africa compared to higher rates in black women in Europe.
The symptoms of SLE may vary in presentation between affected individuals and can change over time. The classic triad of symptoms associated with SLE is a characteristic butterfly rash on the checks and nose, joint pain and fever.
Other symptoms include:
- Severe fatigue
- Swollen or painful joints
- Clotting disorders
- Raynaud’s phenomenon (reduced blood flow to fingers or toes in response to cold or stress causing them to turn white then blue and red).
The renal, gastrointestinal, cardiac and pulmonary systems may also be affected. Antibody tests and urinalysis among others are diagnostic methods used when SLE is suspected and treatment regimens include steroids, corticosteroids and anti-inflammatory drugs.
Discoid Lupus Erythematosus
DLE has the classical presentation of scaly plaques that range from superficial reddening of the skin to tissue around the roots of hair becoming blocked and having a pinkish-violet look, which may occlude follicles and cause scarring. The lesions tend to favor the scalp, face and ears. DLE may occur in association with SLE or it may occur with the absence of systemic manifestations.
Like SLE and all other LE types, the exact etiology of DLE is poorly understood. Furthermore, the predisposing factors, incidence and prevalence are similar to those of SLE. Exacerbation of the disease is common with exposure to the sun and the prognosis is favorable. Standard therapy includes topical corticosteroids and antimalarial drugs and is aimed at limiting scaring and preventing the development of other lesions.
Drug-Induced Lupus Erythematosus and Neonatal Lupus Erythematosus
The most common culprits of DILE are hydralazine, isoniazid and procainamide. Symptoms such as blurred vision, joint pain and swelling, loss of appetite and skin rash sensitive to sunlight tend to occur after using the drug for several months. Cessation of therapy with the offending agent is required.
NLE presents as non-scarring lesions and many researchers believe that it is caused by maternal autoantibodies (antibodies against one’s own tissues) that cross the placenta. It is commonly associated with neonatal dermatologic, cardiac and hepatic clinical manifestations.
Most neonates with NLE tend to have spontaneous disease resolution within 6 months and therefore do not usually require intervention, which would otherwise include corticosteroids and anti-malarial drugs.
Reviewed by Yolanda Smith, BPharm