This chapter covers a broad range of diseases including lupus erythematosus, scleroderma, dermatomyositis and vasculitis.

Lupus Erythematosus

There are many forms of lupus erythematosus with a wide range of manifestations ranging from localised chronic skin disease in discoid lupus erythematosus (DLE) to subacute cutaneous or systemic lupus erythematosus (SLE) with multiple organ disease. These diseases are thought to be caused by a variety of autoantibodies against cellular antigens including DNA, RNA and other proteins.

Treatment options include oral, intralesional and topical corticosteroids (potent to very potent), antimalarials (e.g. hydroxychloroquine) and dapsone.

Sunscreens are essential, with strict sun avoidance (see Chapter 38).

Discoid Lupus Erythematosus

This is the most common form with localised or widespread scaly red papules and plaques with central atrophy and scarring. DLE is more common in women with peak incidence in the forties.

Photosensitivity is present in 50% with 1–5% of cases progressing to SLE. The main sites affected are scalp, face and ears (Figures 42.1 and 42.3). Scarring alopecia can occur.

Clinical features include follicular plugging and adherent scaling with wrinkled epidermal atrophy. Lesions can be hypertrophic (thickened) leading to white or hyperpigmented depressed scars with telangiectasia.

Subacute Cutaneous Lupus Erythematosus

This subtype has non-scarring red annular patches (Figure 42.2) or plaques in sun exposed areas on the upper trunk, neck, face and dorsum of hands. Photosensitivity is present in 70–90%.

Blood tests show positive ANA (anti-nuclear), anti-Ro (anti-SSA) and anti-La (anti-SSB) antibodies. Systemic involvement with kidney disease and leukopenia can occur.

Neonatal lupus erythematosus is a risk in affected women with transplacental transmission of antibodies (see Chapter 26).