The Netherton-syndrome is a rare disease which is probably inherited through an autosomal recessive trait. It is defined by a triad of symptoms: congenital ichthyosiform erythrodermia , trichorrhexis invaginata et nodosa ("bamboo hair") and atopy. Additional disorders affect the immune system, the metabolism of amino acids and the physical development. On the basis of a new case, the cellular immune defect and the genetic background of the disease are more clearly defined. A new form of treatment--a combination of photochemotherapy (PUVA) and systematic application of aromatic retinoid--has so far proved to be successful. In order to establish an accurate diagnosis--a prerequisite for this promising therapeutic approach--diseases with similar symptoms are discussed for comparison.