1 History of Urticaria.- 1.1 Introduction.- 1.2 Nomenclature.- 1.3 Pathogenetic Theories.- 1.4 The Physical Urticarias.- 1.5 Urticaria Pigmentosa.- 1.6 Angio(neurotic)edema.- 1.7 Treatment.- 2 Basic Mechanisms.- 2.1 The Wheal.- 2.2 The Mast Cell.- 2.2.1 Morphological Aspects.- 2.2.2 Mast Cell Heterogeneity.- 2.2.3 Mast Cell Receptors.- 2.2.4 Mast Cell Triggering.- 2.2.5 Modulation of Mast Cell Release.- 2.2.6 Mast Cell Granules.- 2.3 Mediators.- 2.3.1 Histamine.- 2.3.2 5-Hydroxytryptamine (Serotonin).- 2.3.3 Kinins.- 2.3.4 Slow-Reacting Substances (Leukotrienes C4, D4, E4).- 2.3.5 Platelet Activating Factor.- 2.3.6 Prostaglandins.- 2.3.7 Complement.- 2.3.8 Chemotactic Factors.- 2.3.9 Heparin.- 2.3.10 Enzymes and Enzyme Inhibitors.- 2.4 Overview of Pathogenetic Aspects.- 3 Acute and Chronic Urticaria.- 3.1 Definition.- 3.2 Classification.- 3.3 Epidemiology.- 3.3.1 Incidence.- 3.3.2 Age.- 3.3.3 Sex.- 3.3.4 Types of Urticaria.- 3.3.5 Atopy.- 3.4 Clinical Aspects.- 3.4.1 Cutaneous Lesions.- 3.4.2 Noncutaneous Symptomatology.- 3.4.3 Anaphylaxis.- 3.4.4 Serum Sickness.- 3.4.5 Course and Prognosis.- 3.5 Histopathology.- 3.6 Laboratory Findings.- 3.6.1 Leukocytes.- 3.6.2 Immunoglobulins.- 3.6.3 Complement and Protease Inhibitors.- 3.7 Specific Causes of Reactions.- 3.7.1 General Aspect of Drug Reactions.- 3.7.2 Penicillin.- 3.7.3 Sulfonamides and Antibiotics Other Than Penicillin.- 3.7.4 Various Other Drugs.- 3.7.5 Implants.- 3.7.6 Vaccines.- 3.7.7 Blood Products and Substitutes.- 3.7.8 Seminal Plasma.- 3.7.9 Contrast Media.- 3.7.10 Food.- 3.7.11 Infections.- 3.7.12 Inhalants.- 3.7.13 Hormones and Endocrine Disorders.- 3.7.14 Internal Disease.- 3.7.15 Neurological and Psychic Factors.- 3.8 Diagnosis and Differential Diagnosis.- 3.8.1 General Considerations.- 3.8.2 Specific Diseases.- 4 Angioedema.- 4.1 General Aspects and Epidemiology.- 4.2 Classification.- 4.3 Clinical Aspects.- 4.3.1 Cutaneous Symptoms.- 4.3.2 Extracutaneous Symptoms.- 4.4 Associated Diseases.- 4.5 Course and Prognosis.- 4.6 Histology and Ultrastructure.- 4.7 Pathogenesis.- 4.7.1 Biochemical Defects in Hereditary Angioedema.- 4.7.2 Pathogenesis of Acquired Angioedema.- 4.8 Laboratory Findings.- 4.9 Genetics.- 4.10 Diagnosis.- 4.11 Differential Diagnosis.- 5 The Physical Urticarias.- 5.1 General Aspects.- 5.2 Epidemiology and Clinical Aspects.- 5.3 Pathogenesis.- 5.3.1 Passive Transfer.- 5.3.2 Mediators.- 5.3.3 Unifying Pathogenetic Scheme.- 5.4 Dermographic Urticaria (Urticaria Factitia).- 5.4.1 Clinical Aspects and Epidemiology.- 5.4.2 Cutaneous Symptoms.- 5.4.3 Systemic Manifestations and Laboratory Findings.- 5.4.4 Morphological Changes.- 5.4.5 Special Types of Dermographic Urticaria.- 5.4.6 Other Diseases Associated with Dermographic Urticaria.- 5.4.7 Diagnosis.- 5.4.8 Differential Diagnosis.- 5.4.9 Prognosis.- 5.4.10 Pathogenesis.- 5.5 Vibratory Angioedema.- 5.6 Pressure Urticaria.- 5.6.1 Epidemiology.- 5.6.2 Clinical Features.- 5.6.3 Laboratory Findings.- 5.6.4 Associated Diseases.- 5.6.5 Histological Findings.- 5.6.6 Diagnosis.- 5.6.7 Pathomechanisms.- 5.7 Cold Urticaria.- 5.7.1 General Aspects.- 5.7.2 Clinical Features.- 5.7.3 Histological Findings.- 5.7.4 Laboratory Findings.- 5.7.5 Associated Diseases.- 5.7.6 Diagnosis.- 5.7.7 Differential Diagnosis.- 5.7.8 Prognosis.- 5.7.9 Pathogenesis.- 5.7.10 Special Types of Cold Urticaria.- 5.8 Cholinergic Urticaria.- 5.8.1 Epidemiology.- 5.8.2 Local Symptoms.- 5.8.3 Systemic Symptoms.- 5.8.4 Laboratory Findings.- 5.8.5 Histology.- 5.8.6 Associated Diseases.- 5.8.7 Diagnosis.- 5.8.8 Differential Diagnosis.- 5.8.9 Pathogenesis.- 5.8.10 Variant Types of Cholinergic Urticaria and Related Diseases.- 5.9 Solar Urticaria.- 5.9.1 General Aspects and Epidemiology.- 5.9.2 Cutaneous Reactions.- 5.9.3 Systemic Symptoms.- 5.9.4 Laboratory Findings.- 5.9.5 Histology.- 5.9.6 Underlying and Associated Diseases.- 5.9.7 Diagnosis.- 5.9.8 Differential Diagnosis.- 5.9.9 Prognosis.- 5.9.10 Pathogenesis.- 5.10 Heat Contact Urticaria.- 5.10.1 General Aspects.- 5.10.2 Local Reactions.- 5.10.3 Systemic Symptoms.- 5.10.4 Laboratory Findings.- 5.10.5 Associated Diseases.- 5.10.6 Histological Findings.- 5.10.7 Diagnosis.- 5.10.8 Differential Diagnosis.- 5.10.9 Prognosis.- 5.10.10 Pathogenesis.- 5.11 Aquagenic Urticaria.- 5.11.1 General Aspects.- 5.11.2 Clinical Findings.- 5.11.3 Diagnosis and Differential Diagnosis.- 5.11.4 Pathogenesis.- 6 Contact Urticaria.- 6.1 General Aspects and Classification.- 6.2 Clinical Manifestations.- 6.2.1 Local Appearance, Time Course, and Histology.- 6.2.2 Systemic Symptoms.- 6.3 Immunologically Mediated Contact Urticaria.- 6.4 Contact Urticaria due to Histamine Liberators.- 6.5 Venom-Induced Contact Urticaria.- 6.6 Contact Urticaria due to Unknown Mechanisms.- 6.7 Pathomechanisms of Contact Urticaria.- 6.7.1 Mechanism of Release.- 6.7.2 Mediators Involved in Contact Urticaria.- 6.7.3 Local Factors Important for Development of Contact Urticaria.- 6.8 Diagnosis of Contact Urticaria.- 6.8.1 Clinical Diagnosis.- 6.8.2 Diagnostic Skin Tests.- 6.8.3 Further Diagnostic Tests.- 7 Anaphylactoid Reactions.- 7.1 Definition.- 7.2 Classification.- 7.3 Epidemiological Aspects.- 7.4 Agents Eliciting Anaphylactoid Reactions.- 7.4.1 Analgesics.- 7.4.2 Preservatives and Colorings.- 7.4.3 Radiocontrast Media.- 7.4.4 Plasma Expanders.- 7.4.5 Anesthetics.- 7.5 Clinical Features.- 7.5.1 Symptomatology.- 7.5.2 Kinetics of the Reaction.- 7.5.3 Laboratory Findings.- 7.5.4 Prognosis.- 7.6 Diagnosis.- 7.6.1 Patient History.- 7.6.2 Skin Tests.- 7.6.3 Sequential Tests for Vascular Response.- 7.6.4 Oral Provocation Tests.- 7.6.5 In Vitro Tests for Lymphocyte Transformation.- 7.7 Pathogenesis.- 7.7.1 Immunoglobulins, Mast Cells, Mast Cell Mediators.- 7.7.2 Arachidonate Metabolism.- 7.7.3 Involvement of the Complement Pathway.- 7.7.4 Other Theories.- 7.8 Pathogenetic Aspects of Intolerance Reactions to Special Reagents.- 7.8.1 Contrast Media.- 7.8.2 Volume Expanders.- 7.8.3 Drugs for Anesthesia.- 8 Urticarial Vasculitis Syndrome.- 8.1 General Aspects.- 8.2 Epidemiology.- 8.3 Clinical Aspects.- 8.3.1 Cutaneous Manifestations.- 8.3.2 Systemic Manifestations.- 8.4 Histopathology.- 8.5 Immunopathology.- 8.6 Laboratory Findings.- 8.6.1 Erythrocyte Sedimentation Rate.- 8.6.2 Immunoglobulins.- 8.6.3 Complement System.- 8.6.4 Immune Complexes.- 8.7 Diagnosis.- 8.8 Differential Diagnosis.- 8.9 Prognosis.- 8.10 Pathogenesis.- 8.10.1 Immune Complexes.- 8.10.2 Mediators.- 8.10.3 Relationship to the Arthus Reaction.- 8.10.4 Other Pathogenic Factors.- 9 Mastocytosis (Urticaria Pigmentosa).- 9.1 Introduction.- 9.2 Cutaneous Mastocytosis.- 9.3 Systemic Mastocytosis.- 9.4 Symptomatology.- 9.5 Histology.- 9.6 Laboratory Findings.- 9.7 Diagnosis.- 9.8 Pathogenesis.- 9.9 Prognosis.- 10 Diagnosis.- 10.1 Introduction.- 10.2 History.- 10.2.1 Clinical Appearance and Symptoms.- 10.2.2 Potentially Provoking or Associated Factors.- 10.2.3 Physical Examination.- 10.3 Laboratory Procedures.- 10.3.1 Screening Tests.- 10.3.2 Specific Diagnostic Laboratory Tests.- 10.3.3 Laboratory Tests for Diagnosis of IgE-Dependent Allergy (RAST and RIST).- 10.3.4 In Vivo Provocation Tests.- 10.3.5 Tests for Physical Urticarias.- 10.3.6 Oral Challenge Tests.- 10.4 Diagnosis by Avoidance.- 10.4.1 Social Habits and Environmental Factors.- 10.4.2 Drugs.- 10.4.3 Diet.- 10.5 Diagnosis by Therapy.- 11 Therapy.- 11.1 Basic Therapeutic Considerations.- 11.2 Specific Therapeutic Modalities.- 11.2.1 Antihistamines.- 11.2.2 Beta-Adrenergic Agonists.- 11.2.3 Corticosteroids.- 11.2.4 Inhibitors of Mast Cell Secretion.- 11.2.5 Kallikrein Inhibitors.- 11.2.6 Mast Cell Mediator Depletion.- 11.2.7 Miscellaneous Therapeutic Agents.- 11.2.8 Hyposensitization.- 11.3 Treatment of Acute and Chronic Urticaria.- 11.3.1 Acute Urticaria.- 11.3.2 Anaphylaxis.- 11.3.3 Chronic Urticaria.- 11.4 The Physical Urticarias.- 11.4.1 Dermographic Urticaria.- 11.4.2 Cholinergic Urticaria.- 11.4.3 Cold Urticaria.- 11.4.4 Solar Urticaria.- 11.4.5 Heat Contact Urticaria.- 11.4.6 Pressure Urticaria.- 11.5 Mastocytosis.- 11.6 Urticarial Vasculitis Syndrome.- 11.7 Hereditary Angioedema.- 11.7.1 Danazol.- 11.7.2 Plasmin Inhibitors.- 11.7.3 Replacement Therapy with Fresh Frozen Plasma and C1INH.- 11.7.4 Practical Clinical Guidelines.- References.