Cutaneous lupus: discoid and subacute skin lupus, triggers, treatment and sun protection

Lupus is an autoimmune condition in which the immune system attacks the body's own tissues. The NHS describes systemic lupus as a long-term condition that causes joint pain, skin rashes and tiredness. In cutaneous lupus, the skin is the main target. The PCDS classifies it as acute, subacute, intermittent (lupus tumidus) and chronic, which includes discoid lupus, lupus profundus and chilblain lupus.

Because cutaneous lupus can sometimes occur alongside systemic lupus, doctors usually check for involvement of other organs, particularly where the skin changes are widespread. For most people with discoid lupus, the condition stays in the skin.

The PCDS patient leaflet describes DLE as persistent, localised, red-pink or dark, scaly areas of affected skin most often on the head and neck, less often more generalised. It can be uncomfortable or itchy. The cheeks, nose and ears are the commonest sites, including the hollow next to the ear canal, and the eyebrows may be thin. Adherent scale and horny plugs in the hair follicles are common.

Left uncontrolled, DLE causes permanent skin damage such as scarring, darker or lighter pigment changes and sometimes hair loss; the PCDS clinical guidance says scarring alopecia occurs in one-third of patients. It occurs 2 to 3 times more often in women than men and most often develops between 20 and 40 years, though it can occur at any age. Localised DLE affects only the head and neck and is nearly always confined to the skin, whereas generalised DLE is more difficult to treat and more likely to be linked to systemic lupus.

The PCDS says about 50% of DLE patients achieve complete resolution over many years, with a worse outlook when there is Raynaud's phenomenon, chilblains or hair loss.

The PCDS leaflet describes SCLE as scaly, raised and/or ring-shaped skin changes usually affecting sun-exposed areas such as the V of the neckline, scalp, arms and upper back, with the face often unaffected. Most people feel well, though some have fatigue or joint aches. In skin of colour the area may be darker or lighter than the surrounding skin. Unlike DLE, there is no scarring.

Other features can include non-scarring hair loss, a network-like skin pattern (livedo reticularis), Raynaud's phenomenon and mouth ulcers. The leaflet says approximately 10% of cases go on to develop systemic lupus with involvement of organs such as the kidneys and lungs. SCLE is most common in middle-aged women, except when caused by medicines when it often presents in older people.

Approximately one-third of cases are caused by medicines, including some blood pressure and antacid medicines such as proton pump inhibitors. Most drug-induced cases are reversible after the medicine is stopped, although resolution can take up to 12 months, and most improve within 3 months. The leaflet stresses that you should not stop any medicine without first discussing it with your doctor.

The PCDS says that in the majority of cases you will need to be referred to a specialist, who could be a dermatologist or a GP with an extended role in dermatology. In most cases a small sample of skin (a biopsy) is taken to be examined under a microscope to confirm the diagnosis, and other tests may include blood and urine tests.

Blood tests help to look for systemic involvement and for antibodies such as anti-Ro/SSA, which the PCDS guidance links to SCLE. The NHS adds that lupus can be hard to diagnose because the symptoms can be similar to other conditions.

The two most important self-help measures are, according to the PCDS leaflets, stopping smoking and protecting the skin from UV. Smoking tends to make DLE worse and may result in a poorer response to treatment. UV protection means avoiding direct sun, remembering that UV exposure also occurs while walking, gardening and driving, protecting the skin with clothing and a hat and UV-protective sunglasses, using a high protection sunscreen of at least SPF 30 with high UVA protection (4 or 5 star), applying it generously 15 to 30 minutes before going out and reapplying often, and avoiding sunbeds. The sunscreen can be prescribed by a GP because it is used for medical reasons.

Skin treatments may include strong or very strong steroid creams, ointments, gels or lotions, which in DLE can be used safely even on the face under specialist direction, topical calcineurin inhibitors such as pimecrolimus and tacrolimus, and in some localised cases injections of steroids into the skin. If the skin or scalp changes are more severe or do not respond, tablets may be needed: the most commonly used are the antimalarial drugs hydroxychloroquine and mepacrine, and occasionally immunosuppressive therapy.

The PCDS notes that the psychological impact can be significant, affecting work and relationships, and recommends discussing mental health support with a healthcare professional. Lupus UK and, for appearance concerns, Changing Faces are named as sources of support.

The NHS lists joint and muscle pain, extreme tiredness that will not go away, rashes that usually come on after being in the sun, headaches, mouth ulcers, a high temperature, hair loss, weight loss, swollen glands, chest or tummy pain and colour changes of the fingers and toes in the cold among the symptoms of systemic lupus, and advises seeing a GP if you often get them because lupus is better managed if found and treated early.

If you have cutaneous lupus and develop new joint pain, persistent fatigue, swelling of the legs, foamy urine, chest pain on breathing or breathlessness, report them promptly to your GP or specialist.

See a GP for any persistent scaly or red patch on the face, scalp or sun-exposed skin that does not clear, or for new hair loss with scarring. Early treatment reduces the chance of permanent scarring in discoid lupus. Seek urgent medical advice for a widespread blistering rash, fever with a spreading rash, or chest pain and breathlessness.