Many disorders affect both the nervous system and the skin. The complementary—and some would say—diametrically opposite—clinical methods of the dermatologist and the neurologist can in these circumstances reduce an otherwise dauntingly large differential into a more tractable, smaller list. Often triangulation with these and other clinical findings is sufficient for accurate diagnosis, but in other cases, serological or genetic data must be considered before diagnosis is secure.

We have purposely avoided traditional groupings such as phakomatoses, and immunological, infectious, or genetic diseases. Such distinctions are becoming increasingly obscure. Instead, we have organised the roughly 300 disorders with manifestations both in the skin and nervous system into clinically relevant groupings, as they may be first encountered by a practicing physician: neurocutaneous disorders associated with impaired immunity; stroke; neuropathy; meningitis or meningoencephalitis; vesicular lesions; ecchymoses, non-palpable purpura, and petechiae; cafe au lait spots; amyloidosis; rheumatoid arthritis; cutaneous vasculitis; photosensitivity; and melanoma. For disorders mentioned only in the tables, or not at all, the reader is referred to the encyclopaedic text of Fitzpatricket al 1 and more specialised compendia.2 ³