Lupus erythematosus

Lupus erythematosus
Classification and external resources
Specialty	Rheumatology
ICD-10	L93 (ILDS L93.010)
ICD-9-CM	695.4

Lupus erythematosus is a name given to a collection of autoimmune diseases in which the human immune system becomes hyperactive and attacks normal, healthy tissues.^[1] Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs. The most common and severe form is systemic lupus erythematosus.

Classification

Lupus erythematosus may manifest as systemic disease or in a purely cutaneous form also known as incomplete lupus erythematosus. Lupus has four main types:

• systemic
• discoid
• drug-induced
• neonatal

Of these, systemic lupus erythematosus (also known as SLE) is the most common and serious form.

A more thorough categorization of lupus includes the following types:^[2][3]

• acute cutaneous lupus erythematosus
• subacute cutaneous lupus erythematosus
• chronic cutaneous lupus erythematosus
  • discoid lupus erythematosus
    • childhood discoid lupus erythematosus
    • generalized discoid lupus erythematosus
    • localized discoid lupus erythematosus
  • chilblain lupus erythematosus (Hutchinson)
  • lupus erythematosus-lichen planus overlap syndrome
  • lupus erythematosus panniculitis (lupus erythematosus profundus)
  • tumid lupus erythematosus
  • verrucous lupus erythematosus (hypertrophic lupus erythematosus)
• complement deficiency syndromes
• drug-induced lupus erythematosus
• neonatal lupus erythematosus
• systemic lupus erythematosus

Signs and symptoms

Symptoms vary from person to person, and may come and go. Almost everyone with lupus has joint pain and swelling. Some develop arthritis. Frequently affected joints are the fingers, hands, wrists, and knees. Other common symptoms include:

• chest pain when taking a deep breath
• fatigue
• fever with no other cause
• general discomfort, uneasiness, or ill feeling (malaise)
• hair loss
• mouth sores
• sensitivity to sunlight
• skin rash – a "butterfly" rash in about half people with SLE
• swollen lymph nodes^[4]

Photosensitivity

Photosensitivity is a known symptom of lupus, but its relationship to and influence on other aspects of the disease remain to be defined.^[5] Causes of photosensitivity may include:

• change in autoantibody location
• cytotoxicity
• inducing apoptosis with autoantigens in apoptotic blebs
• upregulation of adhesion molecules and cytokines
• inducing nitric oxide synthase expression
• ultraviolet-generated antigenic DNA.
• tumor necrosis factor alpha also seems to play a role in the development of photosensitivity.

Genetics

Causes

It is typically believed that Lupus is influenced by multiple genes. Lupus is usually influenced by gene polymorphisms, 30 of which have now been linked with the disorder. Some of these polymorphisms have been linked very tentatively however, as the role that they play or the degree to which they influence the disease is unknown. Other genes that are commonly thought to be associated with Lupus are those in the Human leukocyte antigen (HLA) family, which are largely related to healthy functioning of the immune system. There have been several cases where a single gene influence appears to be present, but this is rare. When a single gene deficiency does cause Lupus, it is usually attributed to the genes C1, C2, or C4. The influence of sex chromosomes and environmental factors are also noteworthy. Usually, these factors contribute to Lupus by compromising the immune system.^[6]

Age difference

Lupus can develop in any age but most commonly in ages 15 to 44 with varying results. Typically, the manifestation of the disease tends to be more acute in those affected who are of younger age. Women are more likely to get it than men. It is more common for a Native American, African, or Asian person to get Lupus than a Caucasian. Patients with juvenile onset Lupus in particular, are vulnerable to mucocutaneous (alopecia, skin rash, and ulceration of the mucus membranes) manifestations of the disease more so than any other age group. However, patients with late onset Lupus have a much higher mortality rate. Nearly 50% of those with late onset Lupus died of their affliction. This is most likely due to the age of the patients with late onset Lupus since the manifestation of their disease is much less severe than younger patients. Women who are of childbearing age are also particularly at risk.^[7]

Differences in ethnicity

Substantial data have been found to indicate that certain ethnic populations could be more at risk for Lupus Erythematosus, and have a better or worse prognosis. Asian, African, and Native Americans are more likely to get Lupus than Caucasians. Caucasians seem to generally have a more mild manifestation of the disease. Their survival rates after five years were typically around 94%-96%, while patients of African, and some Asian ethnicities had survival rates closer to 79%-92%. The only documented ethnicity that had a higher survival rate than Caucasians were Koreans, who had survival rates nearer to 98%. Among Caucasians, the most common causes of death were complications involving the cardiovascular system, the respiratory system and problems with malignancies.^[8][9]

Treatment

Treatment consists primarily of immunosuppressive drugs (e.g., hydroxychloroquine and corticosteroids). In 2011, the U.S. Food and Drug Administration (FDA) approved the first new drug for lupus in more than 50 years to be used in the US, belimumab.^[10]

Epidemiology

Worldwide

• an estimated 5 million people worldwide have some form of lupus disease.^[11]
• 70% of lupus cases diagnosed are systemic lupus erythematosus.^[11]
• 20% of people with lupus will have a parent or sibling who already has lupus or may develop lupus.^[11]
• about 5% of the children born to individuals with lupus will develop the illness.^[11]

United Kingdom

• SLE affects UK females far more than males at a ratio of 7:1. In other words, females are seven times more likely to have the disease.^[12]
• The estimated number of UK females with SLE is 21,700, and the number of UK males with lupus is 3000—a total of 24,700, or 0.041% of the population.^[12]
• SLE is more common amongst certain ethnic groups than others, especially those of African origin.^[12]

United States

• occurs from infancy to old age, with peak occurrence between ages 15 and 40.^[10]
• affects U.S. females 6 to 10 times more often than males.^[10]
• yields limited prevalence data. Estimates vary and range from 1.8 to 7.6 cases per 100,000 persons per year in parts of the continental United States.^[10]

See also

• List of cutaneous conditions
• List of target antigens in pemphigoid
• List of immunofluorescence findings for autoimmune bullous conditions
• List of human leukocyte antigen alleles associated with cutaneous conditions

References