lupus erythematosus

Last reviewed 01/2018

This embraces a variety of photosensitive conditions ranging from a purely localised cutaneous problem to a multisystem disorder with minimal cutaneous involvement. At the extreme ends, there is almost no overlap and no progress from one clinical presentation to another, but in the middle zone, progress from one clinical form to another has been reported in a proportion of cases. The condition is more common in women than in men, and the systemic form tends to affect a younger age group.

All forms are characterised by perifollicular inflammation which is usually followed by scarring. The classic lesion of LE is the atrophic red, scaly plaque with follicular plugging. The basal layer of the epidermis shows a characteristic pattern of damage - liquefaction degeneration - which gives the dermo-epidermal junction a ragged, 'saw toothed' outline. Linear deposits of immunoglobulins can be demonstrated in the basement membrane by direct immunofluorescence microscopy.

Circulating autoantibodies are a useful guide to the type of LE and it's activity. A high titre of antinuclear antibody suggests systemic disease and the presence of antibodies to double-stranded DNA suggests active disease. Circulating autoantibodies are rare in patients with localised cutaneous problems although those with subacute cutaneous LE may demonstrate anti-Ro or anti-La antibodies.