Discoid lupus erythematosus
Discoid lupus erythematosus is not the same as systemic lupus erythematosus. In systemic lupus erythematosus internal organs are also affected. Patients with systemic lupus erythematosus can have features of discoid lupus erythematosus. Also discoid lupus erythematosus can progress to systemic lupus erythematosus. The discoid lupus erythematosus treatment includes sunscreens, steroids and antimalarial medications.
Discoid lupus erythematosus is an autoimmune disease which occurs in genetically predisposed individuals. This disease is more common in African Americans than Asians or Caucasians. It is more common in females. It may occur in any age but is common in individuals between 20 and 40 years of age.
Discoid lupus erythematosus - symptoms
In most of the individuals affected by discoid lupus erythematosus symptoms may not be overt. In those who are symptomatic most present with mild itching and pain in the skin lesions. They may sometime have symptoms of joint pain and joint swelling. In about 5% of the individuals with discoid lupus erythematosus symptoms of systemic lupus erythematosus may be seen. Many other skin diseases are associated with discoid lupus erythematosus. These include:
- Non-melanoma skin cancer especially in dark skinned individuals
- Porphyria cutanea tarda
- Lichen planus
Features of skin lesions in discoid lupus erythematosus
The skin lesions of discoid lupus erythematosus are very characteristic. The skin lesions are round and slightly raised from the surface. The lesions are initially reddish and are covered by scales. The scales later get thickened with changes in color. In the center of the lesion, the scales are light colored. Along the borders the scales are darker. As the lesions grow they merge with each other. Resolution of these active skin lesions results in wasting and scarring of the skin.
The skin lesions may have any or all the above mentioned features. The skin lesions are mostly found on the exposed areas of the body. Scalp is commonly involved and the scarring of scalp results in hair loss. The skin lesions are very sensitive to the sun. The exposed skin develops sunburns and the skin lesion gets worsened.
Types of discoid lupus erythematosus
Discoid lupus erythematosus can be localized or widespread. In localized discoid lupus erythematosus, the head and neck are involved. In wide spread discoid lupus erythematosus other parts of the body are also affected. Patients with widespread discoid lupus erythematosus may develop systemic lupus erythematosus later. Of the two types the widespread type is difficult to treat.
Hypertrophic discoid lupus erythematosus is another subset of discoid lupus erythematosus in which the lesions are wart like. The lesions are mainly seen on the back of the arm. This type of discoid lupus erythematosus is very difficult to treat.
Cause and Diagnosis of discoid lupus erythematosus
The exact cause of discoid lupus erythematosus is not known. It is an autoimmune disease. In autoimmune disease, the cells of the immune system act on the cells of the body itself. In discoid lupus erythematosus, the cells of the immune system act on the skin of genetically predisposed individuals resulting in inflammation and characteristic skin lesions.
Diagnosis of discoid lupus erythematosus is done by the following laboratory tests.
- ANA test – positive in about 20% of the patients with discoid lupus erythematosus
- Other antibodies like anti-Ro(SS-A), antinative DNA and anti-Sm antibodies are positive in less than 5% of patients with discoid lupus erythematosus
- White blood cell count – The count will be low
- Erythrocyte sedimentation rate will be elevated
- Rheumatoid factor- may be positive
- Urinalysis – Urine test may show involvement of kidneys. There may be high protein content in the urine
Biopsy of the skin
- Positive direct immunofluorescence test
- Histopathology test will show features of involvement of various layers of the skin
Discoid lupus erythematosus - Treatment
In patients affected by discoid lupus erythematosus, treatment mainly consists of sunscreens, steroids and antimalarial medications. The goals of discoid lupus erythematosus treatment are to prevent worsening of the lesions, to prevent the development of new lesions and to improve the appearance of the affected individual.
Repeated clinical evaluation is very important to assess the progression of the disease. The first and the foremost step in the treatment of discoid lupus erythematosus is to avoid exposure to sun as individuals with discoid lupus erythematosus can develop sunburns when exposed to sun. Sunscreens, protective clothing and protective makeup including wig are helpful in preventing damage to the skin.
The various medications that are found to be effective in the treatment of discoid lupus erythematosus are:
- Medications that suppress the immune system
Steroids can be applied topically or can be injected in to the skin lesions for improvement of symptoms. The type and preparation of the steroids used for treatment depends on site of involvement. For the lesions on the scalp, steroid lotions or foams are used. For the lesions of the face, weaker steroids are used. For Hypertrophic lesions potent steroids are used. Triamcinolone acetonide is the steroid that can be injected in to the skin lesions.
Antimalarial medications are equally effective in controlling the symptoms. But they are less effective in patients who smoke. Hydroxychloroquine is a very effective antimalarial medication in the treatment of discoid lupus erythematosus. If antimalarial medications are not effective then medications like thalidomide can be used along with them.
Medications which suppress the immune system can also be used to treat discoid lupus erythematosus. Some of the medications which come under this category are methotrexate, azathioprine and mycophenolate mofetil. Topical medications include tacrolimus, pimecrolimus and imiquimod.
If the skin lesions are burnt out they can be excised. But sometimes this may result in reactivation of the skin lesions. Laser therapy is also used for certain type of skin lesions of discoid lupus erythematosus.