special subjects
Idiopathic Environmental Intolerance
Diagnosis
Exclusion of other causes Diagnosis of idiopathic environmental intolerance initially involves exclusion of known disorders with similar manifestations: Overview of Allergic and Atopic Disorders (eg, allergic rhinitis, food allergies) Atopic disorders (eg, Asthma , Building-related illnesses Endocrine disorders (eg, Carcinoid Syndrome , Atopic disorders are excluded based on a typical clinical history, skin-prick testing, serum assays of specific IgE, or all 3. Consultation with an allergy specialist may be helpful. Specific building-related illnesses , in which many people who spend time in the same building develop symptoms, should be considered. If symptoms and signs are not strongly suggestive of a "connective tissue" or systemic autoimmune rheumatologic disorder (eg, joint, skin and/or mucous membrane manifestations), testing for a wide range of autoantibodies (eg, antinuclear antibodies [ANA], rheumatoid factor, extractable nuclear antigens [ENA]) should be avoided. In such cases, pretest probability is low and false-positive results are far more likely than true-positive results; a weakly positive ANA is present in about 20% of the general population. 