Discoid lupus is a rare skin condition but it is very long-lasting. It is usually sensitive to sunlight and causes scarring when the lesions heal.
What is discoid lupus?
Discoid lupus is an uncommon but long-lasting (chronic) skin rash, which is usually made worse by exposure to sunlight (it is photosensitive). Discoid lupus is also called discoid lupus erythematosus (DLE). Discoid lupus can be localised to affect a small area of skin, or may be more widespread.
'Discoid' lupus erythematosus is confined to the skin and is not associated with symptoms from other organs. A more severe form is called systemic lupus erythematosus (SLE), which can affect internal organs. Discoid lupus can cause permanent scarring if it is not treated or if treatment is not effective.
What causes discoid lupus?
It is thought that discoid lupus is an autoimmune disease. This means that some of the proteins made by the body to fight infection (antibodies), mistakenly attack normal cells in our body. in discoid lupus it is the skin cells that are attacked by these antibodies.
Some families may carry genes that increase the risk of developing discoid lupus. It is thought that discoid lupus is caused by a combination of environmental factors and genetics.
How common is discoid lupus?
Discoid lupus affects between 2 and 5 out of every 10,000 people. Women are much more often affected than men. Discoid lupus usually first starts in people aged between 20 and 40 years. Discoid lupus is more common in people who smoke.
A small number of people with systemic lupus erythematosis also have discoid lupus.
Discoid lupus may be triggered or made worse by stress, infection or trauma. Some medicines may also trigger discoid lupus.
What are the symptoms of discoid lupus
Discoid lupus causes red scaly patches. When the lesions eventually resolve, they may leave areas of increased skin pigmentation, destruction (atrophy) of the affected skin, and white scars.
The lesions don't usually cause any other symptoms but may cause itching or pain. Discoid lupus mainly affects areas exposed to sunlight, such as the cheeks, nose, ears, upper back, neck and the backs of the hands. It may rarely occur on the palms or the soles.
The discoid lupus lesions may cause wart-like lesions, most often on the back of the arms.
Discoid lupus may affect the scalp and cause permanent scarring with hair loss (alopecia). The condition may also affect the lips and the inside of the mouth, causing ulcers and scaling.
How can discoid lupus be diagnosed?
Your doctor will usually be able to make the diagnosis just on the appearance of your skin. However, you will usually be referred to a dermatologist for further assessment and treatment. Sometimes tests are needed to confirm the diagnosis. These tests may include blood and urine tests, and taking a skin sample (skin biopsy).
What are the treatments for discoid lupus?
Like many autoimmune conditions, discoid lupus is generally a lifelong condition and there is no cure. However, there are treatments available that are usually effective and can help keep symptoms under control.
Smoking can make discoid lupus worse and may also result in a poor response to treatment.
- Protect your skin with clothing and sunscreen. Wear a hat to protect your face. Wear a pair of UV protective sunglasses.
- Use daily sunscreen when appropriate. You should use a sunscreen with a high sun protection factor (SPF 30 or more) to protect against UVB and UVA.
- Strictly avoiding sunlight can reduce vitamin D levels. You should have a diet high in vitamin D (oily fish, eggs, meat, fortified margarines and cereals) and it may be worth taking vitamin D supplements.
- Strong steroid creams or steroid injections into the lesions. These can help to reduce inflammation but can thin the skin if used for too long.
- Steroid-sparing creams and ointments. Examples include calcineurin inhibitors (such as tacrolimus ointment or pimecrolimus cream). These treatments do not contain steroid and they act on the immune system to help reduce inflammation.
- Topical imiquimod cream is an alternative treatment for widespread discoid lupus.
- Skin camouflage can be used where there are areas of plaque involvement or if scarring occurs.
Tablets and injections
- Anti-malarial tablets including hydroxychloroquine and mepacrine. These medications reduce inflammation and so help to control discoid lupus.
- Steroid tablets may be helpful for severe, extensive or scarring discoid lupus.
- If there is no response to standard therapy, other medications may be used - for example, immunosuppressant medicines, such as azathioprine, methotrexate or mycophenolate mofetil. There are risks associated with these treatments and so they are reserved for severe discoid lupus or when other treatments have not been effective.
- Burned-out scarred lesions may be surgically removed.
- Photodynamic therapy can be effective for some cases. Photodynamic therapy involves using a light-sensitive medicine and a light source to destroy abnormal cells.
- Laser therapy may also be considered for lesions covered with prominent small 'spider' blood vessels (telangiectasias).
What are the complications of discoid lupus?
- About 1 in 20 people with discoid lupus go on the develop systemic lupus erythematosus. The risk is greater for children who develop discoid lupus.
- Skin cancers (basal cell carcinoma or squamous cell carcinoma) may occur but this is unusual.
- Dark skin may lose its protection against sunlight because of loss of pigment (depigmentation).
What is the outlook (prognosis)?
Discoid lupus tends to heal with scarring, hair loss and pigment changes if effective treatment is not started early. Pain in the lesions may continue and scars and skin destruction (atrophy) will be permanent.
However these complications can be greatly reduced by early diagnosis and effective treatment.
Further reading and references
Okon LG, Werth VP; Cutaneous lupus erythematosus: diagnosis and treatment. Best Pract Res Clin Rheumatol. 2013 Jun27(3):391-404. doi: 10.1016/j.berh.2013.07.008.
Discoid Lupus Erythematosus (DLE); DermIS (Dermatology Information System)
Cutaneous lupus erythematosus; DermNet NZ
Bockle BC, Sepp NT; Smoking is highly associated with discoid lupus erythematosus and lupus erythematosus tumidus: analysis of 405 patients. Lupus. 2015 Jun24(7):669-74. doi: 10.1177/0961203314559630. Epub 2014 Nov 19.