List of syndromes and diseases with unknown etiologies
International Statistical Classification of Diseases and Related Health Problems recognized *Pityriasis rosea 696.3 *Metabolic syndrome 277.7 *Irritable bowel syndrome 564.1 *Alzheimer's disease 331.0 *Fibromyalgia 729.1 *Chronic fatigue syndrome 780.71 *Balanitis xerotica obliterans *Anaphylactoid purpura *Sarcoidosis 135 *Prurigo nodularis 698.3
International Statistical Classification of Diseases and Related Health Problems unrecognized *Syndrome X *Sick building syndrome *Gulf War syndrome *Multiple chemical sensitivity