[Leg discoloration].

Many patients present with discolouration of the legs or with non-ulcerating skin lesions, the most frequent causes being chronic venous insufficiency or other chronic or acute states of congestion. Erysipelas (cellulitis) is also a frequent example of a bacterial skin infection. A complex differential diagnosis arises from all types of immune-mediated skin lesions, opening up the broad spectrum of inflammatory systemic disease, such as vasculitis and sarcoidosis. Livedo like lesions and skin involvement in borreliosis are challenging to classify but of considerable clinical importance. The present review focuses on the description of underlying diseases as well as on diagnosis and differential diagnosis. Therapeutic considerations are discussed in less detail.