Discoid lupus erythematosus (DLE) is a chronic autoimmune skin condition characterized by erythematous lesions with scaly and crusty appearances. Discoid lupus erythematosus can be categorized into localized, generalized, and childhood DLE .
Most patients with discoid lupus erythematosus are asymptomatic, however, some patients may experience pain and pruritus in the lesions. A recent study revealed that 16% of patients with DLE may develop systemic manifestations of the disease within 3 years of onset of diagnosis. .
Systemic involvement of DLE presents with clinical features of SLE, therefore , there should be a detailed evaluation to detect serologic abnormalities, hematologic disorders, serosal inflammation such as pleuritis and pericarditis, neurological sequalae, and renal abnormalities.
Malignant transformation of DLE is rare, however, skin cancer may be more common among blacks because of the absence of pigmentation in the chronic lesions, coupled with the chronic inflammation and continuous sun exposure. Risk factors for squamous cell carcinoma include lip involvement of lesions, early age of onset, smoking, male gender, and recalcitrance of the disease .
Lesions in DLE are usually characteristic comprising of erythematous papules or plaques with scaly appearances. As the lesions progress, the scales become thickened and coalescent. There may be central hypopigmentation of the lesions with hyperpigmentation at the active peripheral borders of the lesions. Lesions appear in a centrifugal pattern and may coalesce. These lesions heal with scars. The lesions may present with dilation of the follicular openings which are closed by keratinous plugs. Lesions are mainly found in the sun-exposed areas of the body.
The early lesions may be indistinguishable from those which occur in subacute cutaneous lupus erythematosus. The scalp is a very common site of occurrence of the skin lesions an it may result in irreversible alopecia.
In DLE, the lesions may be localized or generalized. Lesions are said to be localized if they involve only the head and neck regions, and when they affect additional areas of the body, they are described as generalized DLE. Generalized DLE is mostly associated with hematologic abnormalities and abnormal serologic findings. Furthermore, generalized DLE is more refractory to treatment and is more likely to be associated with SLE. The palms and soles are affected in less than 2% of patients with DLE. .
Some cases of DLE present with hypertrophic lesions which have a wart-like appearance, these lesions commonly affect the extensor arms and are generally unresponsive to treatment .
Lupus panniculitis is a form of chronic cutaneous lupus erythematosus which is characterized by inflammatory and destructive changes in the subcutaneous adipose tissue. This condition may coexist with DLE .
Baseline laboratory blood test is necessary in the diagnosis of DLE. These include complete blood count with the white blood cell count often reduced and erythrocyte sedimantation rate (ESR) which is typically raised. Rheumatoid factor may be positive in DLE. A negative result doesn't exclude DLE.
Serology is also important in the diagnosis of discoid lupus erythematosis. Serology reveals positive antinuclear antibody(ANA) findings in 20% of cases of DLE. Complements are often reduced.
Urinalysis may be necessary to exclude renal involvement. Albuminuria suggests kidney involvement.
These laboratory investigations should be ordered periodically to determine the absence or presence of systemic progression.
Biopsy is the most sensitive and specific investigation for DLE. The features on histology are usually characteristic but may depend on the type and duration of the disease. A direct positive immunoflourescence is observed in the biopsy samples in most cases of DLE.
Treatment is aimed at controlling the existing skin lesions, preventing development of new lesions, preventing complications, and improving cosmesis.
Topical corticosteroids and antimalarials are the main drugs of choice for treating DLE.
Intralesional corticosteroids are the preferred form of administration of corticosteroids and are administered into the individual lesions. Oral corticosteroids are avoided because of adverse effects of prolonged use of the drug. A medium-strength corticosteroid such as triamcinolone is usually administered topically first. Low-strength corticosteroids such as hydrocortisone are preferable for facial lesions. However, if both forms of corticosteroids fail to resolve the symptoms, a high-strength corticosteroid such as bethametasone becomes necessary. These high potency corticosteroid are also recommended as first-line for hypertrophic lesions.
If the lesions remain unresolved upon treatment with topical and intraleional corticosteroid, antimalarials are considered with hydroxychloroquine being the drug of choice. If hydroxychloroquine produces no resolution of the lesions after a period of two months of therapy, chloroquine should be used. However, antimalarial therapy should be provided continuously for 1 to 2 years for complete resolution of the lesions. Corticosteroid treatment should be given concurrently with antimalarial treatment and should be discontinued after completion of antimalarial treatment.
In cases where antimalarial treatment is unsuccessful, immunosuppressant treatment is considered next. Effective immunosuppressants include azathioprine, mycophenolate mofetil, and methotrexate. These are also particularly effective in the treatment of refractory cases of DLE.
Oral thalidomide is considered if all other treatments have failed. However, thalidomide is recommended only for remission induction because of its tendency for neural damge. Although thalidomide neurotoxicity is not dose-dependent, low doses could be safe.
Studies have identified topical tacrolimus and pimecrolimus as useful alternative drugs in the treatment of DLE and other CLE lesions. These studies have not provided concrete evidence to establish their safety and effectiveness.
Supportive treatment for DLE include limited sun exposure especially during the hours when sunlight is most intense, usually between 10 am to 3 pm. Occlusive clothing and sunscreens are recommended. Smoking cessation is also critical in preventing progression and worsening of the disease. Cosmetic products to mask the lesions are also recommended.
In cases of DLE with telegiectasia and chronic erythema, surgery including photothermolytic ablation of the dilated vessels may be recommended. This procedure is called pulsed eye laser treatment and it has been shown to be very effective for recalcitrant cases of DLE. Surgical excision of scarred lesions is also effective, although it may reactivate latent lesions.
Discoid lupus erythematosus may not cause mortality, however, it may be associated with significant morbidity. The condition may cause significant burning and pain caused by the lesions, and considerable cosmetic problems. In a few cases, discoid lupus erythematosus may cause fatal sequelae if there is systemic involvement. Although malignant transformation of the lesions are rare, prompt skin biopsy is recommended in case of suggestive malignant lesions . Sunlight is a known exacerbating factor of DLE lesions.
Several studies have identified smoking as a risk factor for DLE. These studies have also indicated ultraviolet radiation as a precipitating and aggravating factor of DLE  . DLE may also develop within areas of skin which have been injured or affected by physical trauma, this is known as koebner phenomenon.
DLE is thought to be a result of autoimmune mechanisms as it has been linked to some major histocompatibility complex antigens. Other studies indicate that genetic factors may contribute to the etiology of DLE .
SLE has a worldwide prevalence of 17 to 48 cases per 100,000 people. SLE most commonly occurs in individuals aged 40-60 years with onset at the age of 20-30 years. SLE is commoner in women than men with a female to male ratio of 10:1.
DLE accounts for 50-85% of all cases of cutaneous lupus erythematosus and it is more common among women than men with a female to male ratio of 3:1.
DLE is also more common among African Americans than whites or Asians. DLE occurs most commonly among persons aged between 20 and 40 years, however, it may occur at any age.
The exact mechanism of development of cutaneous lupus erythematosus in general is not clearly understood. However, leading theories have indicated that an autoimmune process may be responsible for the disease. This is because of the identification of IgG and C3 in the epidermal basement membrane which is the site of the autoimmune damage .
In chronic DLE, as compared to acute and subacute cutaneous lupus erythematosus, there is a much higher concentration of inflammatory infiltrates which mostly comprise of T cells. Additionally, in chronic DLE , the inflammatory cell infiltrates extend to the deeper reticular dermis and subcutaneous tissue in contrast to findings in subacute and acute chronic lupus erythematosus in which the inflammatory cell infiltrates are confined to the outer dermis.
Researchers have suggested that apoptosis of keratinocytes may be the critical occurrence in the etiology of cutaneous lupus erythematosus .
To reduce triggers or flares of the lesions in discoid lupus erythematosus, restriction of exposure to sunlight is advised. This can be achieved by using occlusive clothing and sunscreens. UV-blocking films may be applied to window glasses to prevent reflection of sunlight into the rooms. However, vitamin D supplements are necessary because of the sunlight restriction. Smoking cessation also prevents precipitation of flares of DLE.
Acute CLE is characterized by malar rash which may spread across the nasal bridge. The lesions do not involve the nasolabial folds. Furthermore, acute CLE may present with generalized morbilliform eruptions on the hands sparing the joint areas. Subacute CLE is characterized by annular plaques affecting sun-exposed areas only. Chronic CLE consists of three subdivisons including discoid lupus erythematosus, lupus panniculitis, and timid lupus.
The lesions in discoid lupus erythematosus are erythematous or violaceous plaques with a scaly appearance and a characteristic keratinous plugging on the openings of each lesion.The lesions typically heal with scarring.
DLE may be localized to the skin without systemic features. However, in other cases, it may progress to systemic lupus erythematosus (SLE). Approximately 16.7% of cases of DLE progress to SLE within 3 years from onset of DLE  . Often, the secondary SLE manifestations do not fulfill more than 4 of the 11 criteria for the diagnosis of SLE as set by the American College of Rheumatology 
Diagnosis of DLE is mainly clinical, however, series of laboratory investigations may be necessary to exclude systemic involvement. Serology may be needed to confirm antinuclear antibody (ANA) titers. Skin biopsy is the most sensitive test for DLE.
Treatment of choice for DLE is topical corticosteroid and antimalarials. Corticosteroids are the first line of treatment, while antimalarials and immunosupressants are used respectively if the preceeding medical therapy fails. Surgery may be considered for certain lesions.
Discoid lupus erythematosus (DLE) is a rare skin disease characterized by scaly and crusty rashes affecting mainly the sun-exposed areas of the body. Discoid lupus erythematosus is within a spectrum of skin diseases called cutaneous lupus erythematosus and it is characterized by only skin lesions. Another disease condition in this broad group is called systemic lupus erythematosus which causes both skin rashes and disorders of the internal organs. All of these diseases are worsened by sunlight.
Although the cause of this skin condition is not fully understood, some researchers have suggested that it may result from autoimmune mechanism, which refers to a phenomenon whereby the body's antibodies attack different tissues in the body. This results because the antibodies confuse these tissues for foreign harmful materials from which they must protect the body. In the case of DLE, the antibodies confuse the normal skin cells for foreign objects and attack them causing the skin lesions . it is typically worsened by exposure to sunlight. Tobacco smoking and physical trauma to the skin have also been suggested to contribute to the development of this condition.
DLE affects both sexes and all age groups, however, it is most common among women aged between 20 and 40 years.
The skin presents with red, itchy, and scaly or crusty rashes which heal with bad scars. In some patients , there may be no symptoms at all. The only problem in patients with DLE is the bad appearance of their skin.
DLE typically causes skin rashes in the face and scalp, although could affect every other skin area. In the scalp, DLE could result in irreversible hair loss.
Typically, a skin biopsy may be necessary to make a diagnosis of DLE, the biopsied sample is viewed under the microscope to detect unique features of this disease. Laboratory blood and urine tests are needed to exclude SLE which is the type that affects internal organs.
DLE doesn't have a cure, the available drugs just help to reduce the symptoms of the disease. First of these drugs to be recommended and prescribed by a doctor is corticosteroid ointments or injections which are administered directly into the skin rashes. Corticosteroid tablets have more detriments than benefits, so would be avoided by doctors for the treatment of DLE.
If these drugs have been administered for a period, but the skin rashes do not improve, antimalarials would be prescribed. Now these drugs are not used because of their antimalarial effect, but because of their additional ability to suppress inflammation significantly. The commonest antimalarial used is hydroxychloroqine which could also be prescribed with mepacrine, another antimalarial , to increase its safety and effectiveness. The only concern with hydroxychloroquine is its ability to cause eye problems if taken at high doses. Doctors would conduct eye tests to determine if this drug is suitable for you.
After about 2 months of receiving antimalarial treatment, if no improvement is recorded, certain drugs which serve as suppressants of the immune system would be prescribed. Examples of these include methotrexate and azathioprine.
Self care is also important in the management and control of DLE. Important self-care tips include limiting your exposure to sunlight by using a good sunscreen and wearing clothes that cover your arms, shoulders and legs well. Dark clothing is preferable to reflect sun rays from the cloth. A hat is advised to reduce sun exposure to the face and scalp.