The word lupus' (wolf) comes from the old idea that skin lesions on the face resembled wolf bites. The skin is frequently involved in lupus. Almost any type of skin rash can occur - some of the main skin patterns are described below.
Key points
• 'Butterfly' rash on face
• Rashes on hands and elbows
• Discoid lupus can cause scarring
• Livedo (blotchy circulation) is common
• Plaquenil® is a safe and useful medicine
Systemic lupus erythematosus: skin patterns
The classical picture is of the pinkish, flat rash spread either diffusely or patchily over the face, trunk and limbs. On the face, it can appear in a butterfly rash across the cheeks and nose. It commonly also affects the V of the neck, the tips of the ear lobes and the eyebrows.
The hands and elbows are often involved. On the elbows, there may be small (1 mm) red spots, while on the hands, the picture can vary from severe (a peeling red rash especially on the palms) to mild (pinkish/red discoloration at the nail beds). Although the skin rash is characteristically made worse by sunlight exposure (eg, after a summer vacation), this is not always the case.
Hair loss is a common association, sometimes widespread and severe (eg, hair on the pillow in the morning, not simply on the comb). In systemic lupus, the hair generally grows back fully with successful treatment.
Subacute cutaneous lupus erythematosus (SCLE)
This is a very characteristic skin rash that once seen is never forgotten. The lesions are usually circular or geographic with a distinct border. They often occur on the chest and upper arm.
This rash is associated with a specific blood antibody called anti-Ro. It is very sensitive to UV light, and fortunately usually responds very well to antimalarial treatment. It usually has a good prognosis. The circular nature of the skin lesions means that sometimes the condition is mistaken for a fungal infection.
In pregnancy, anti-Ro antibodies can cross the placenta, and occasionally, babies born to anti-Ro-positive mothers develop a very similar rash, which disappears as the weeks go by and the mother's anti-Ro antibodies are cleared away.
Discoid lupus
This is predominantly a skin condition, with only 5% or so of patients developing systemic lupus. Nevertheless, it can be a serious and debilitating condition. The skin becomes roughened and scaly as well as inflamed, and the continuing process can lead to permanent scarring. Unfortunately the main lesions are often on the face and cheeks, nose, ears and scalp, where severe hair loss can occur. Mouth ulcers can be an unpleasant feature. Patchy lesions (sometimes looking like psoriasis) can occur on the arms, legs, abdomen, and hands. The nails can become affected with thickening, ridging and damage.
In general, discoid lupus has a completely different appearance from the rashes of systemic lupus. While discoid skin lesions can be severe, the majority do respond to treatment (generally initially with antimalarial drugs).
There is a 5% risk of systemic (internal) disease, and because some patients with discoid lupus also have Hughes syndrome, a full investigation is always advisable.
Livedo
This is the name given to a skin condition in which the skin appears mottled, giving a 'map of the word' appearance. It is always worse in cold weather. Many healthy people get livedo, for example, young women in particular get livedo on the knees. However, prominent and widespread livedo can indicate one of a number of health problems, particularly those affecting the circulation.
There is one condition especially associated with livedo - Hughes syndrome. Patients with sticky blood including lupus patients with the condition) frequently have livedo, a telltale sign helpful in diagnosis.
The livedo itself does not constitute a major clinical problem. It often improves when anti-clotting treatment is started.
Chilblains
Some patients develop cold finger and toe circulation, leading to small painful sores (chilblains) on the tips of the digits. In some patients, the tendency to chilblains goes back to childhood, antedating the diagnosis of lupus by many years. Some dermatologists give the name lupus pernio to a particularly prominent form of circulation change with chilblains. However, the presence of these lesions, whilst unpleasant, does not confer any different (or worse) outlook for lupus in general.
Lupus profundus
Just to complete the list, lupus profundus is a rare type of lupus that affects the deeper tissues under the skin, notably the fat. The condition is characterised by uncomfortable or even painful areas of lumpiness under the skin, which leads to visible (and sometimes disfiguring) pits and bumps on the arms, legs, trunk, and unfortunately, occasionally on the face. Although it is an unpleasant and occasionally disfiguring condition, it rarely affects internal organs such as the kidney.
Treatment
Treatment of skin lupus is usually very effective. The mainstay of treatment is the antimalarial drug family - Plaquenil® (hydroxychloroquine) is the first and best choice, and Mepacrine® can be used for more resistant cases.
For patients with more severe skin problems, especially for more resistant cases of discoid lupus or lupus profundus, a number of other drugs are used, with varying degrees of success. These drugs include thalidomide (limited to non-childbearing patients),
azathioprine, methotrexate, mofetil and, occasionally, intravenous immunoglobulins.
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