[Lupus erythematosus. Wide range of symptoms through clinical variation, associated diseases and imitators]

The typical clinical forms of cutaneous lupus erythematosus (LE) are the butterfly rash, acute, subacute and chronic cutaneous lupus, intermediate lupus (lupus tumidus), chilblain- and bullous lupus, lupus profundus, and ulcerating lesions on the mucous membrane. Besides the typical lupus forms, nonspecific skin lesions are also observed such as dermal mucinosis, acneiform skin lesions, different variants of livedo, necrotizing vasculitis with ulcers, purpura, urticaria vasculitis, neutrophilic dermatosis, hyperpigmentation, hair and nail changes as well as overlap syndromes with erythema multiforme, scleroderma, Sjögren syndrome, Raynaud phenomenon, lichen planus, bullous pemphigoid und psoriasis. There are lupus imitators which create differential diagnostic challenges, such as infections with atypical mycobacteria or subcutaneous T-cell lymphoma both of which are similar to lupus profundus. All these skin lesions can present as maximal pathological findings seen in lupus or be caused by a variety of pathological laboratory findings such as the anti-phospholipid antibodies or a deficiency of complement factors. In the latter situation severe lupus often with complications can be expected.