A malar rash (from

Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

‘jaw, cheek-bone’), also called butterfly rash, is a medical sign consisting of a characteristic form of facial

rash A rash is a change of the human skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, c ...

. It is often seen in lupus erythematosus. More rarely, it is also seen in other diseases, such as pellagra,

dermatomyositis Dermatomyositis (DM) is a long-term inflammatory disorder which affects skin and the muscles. Its symptoms are generally a skin rash and worsening muscle weakness over time. These may occur suddenly or develop over months. Other symptoms may inc ...

, and Bloom syndrome. A malar rash of lupus is red or purplish and mildly scaly. It has the shape of a butterfly, and involves the bridge of the nose. Notably, the rash spares the nasolabial folds of the face, which contributes to its characteristic appearance. It is usually macular with sharp edges, and not itchy. There are may conditions which can cause rashes with a similar appearance to a malar rash. A malar rash is present in approximately 46–65% of people with lupus.

Definition

A malar rash of lupus is red or purplish and mildly scaly. It has the characteristic shape of a butterfly, and involves the bridge of the nose. Notably, the rash spares the nasolabial folds of the face, which contributes to its characteristic appearance. It is usually macular with sharp edges, and not itchy. The rash can be transient or progressive with involvement of other parts of the facial skin. While some literature has described the slapped-cheek rash of fifth disease as a malar rash, it differs slightly in that the nose is typically spared.

Differential diagnosis

There are many conditions which can cause rashes with a similar appearance to a malar rash. These include: * lupus erythematosus * pellagra *

* Bloom syndrome Lupus causes up to 96% of all cases of malar rash. Where lupus is suspected, further

medical test A medical test is a medical procedure performed to detect, diagnose, or monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic ...

s and a detailed history and examination are necessary to differentiate it from other conditions. These tests may include a test for the presence of

anti-nuclear antibody Antinuclear antibodies (ANAs, also known as antinuclear factor or ANF) are autoantibodies that bind to contents of the cell nucleus. In normal individuals, the immune system produces antibodies to foreign proteins (antigens) but not to human prot ...

in the blood as a

screening Screening may refer to: * Screening cultures, a type a medical test that is done to find an infection * Screening (economics), a strategy of combating adverse selection (includes sorting resumes to select employees) * Screening (environmental), ...

test, which is not specific for lupus erythematosus.

Epidemiology

A malar rash is present in approximately 46–65% of people with lupus, with an average of 57% of lupus patients having it across all populations. This percentage varies between different populations.

History

A malar rash is often known more colloquially as a butterfly rash due to its distinctive appearance.

References

External links