physical urticarias: and c) other urticarial disorders such as exercise-induced urticaria. • Urticaria occurs frequently with a lifetime prevalence above 20%. • Except for acute urticaria, diagnostic and therapeutic procedures can be complex and referral to a specialist is often required. • Untreated, chronic urticaria has a severe impact on quality of life and impairs productivity by up to 30%. • The socio-economic impact of urticaria is great, since it is a disease which primarily occurs in people of working age. • Moderate to severe urticaria requires specialist treatment. In many health care systems worldwide, access to specialty care is insufficient. Allergy to Drugs and Biological Agents • Adverse drug reactions (ADR) may affect up to 1/10 of the world’s population and affect up to 20% of all hospitalized patients. • More than 10% of all ADR are unpredictable drug hypersensitivity reactions (DHR). • Both under-diagnosis and over-diagnosis are common. • The most common DHR involve antibiotics such as penicillins, cephalosporins, and sulfonamides, and aspirin and other non steroidal anti-inflammatory drugs. WAO White Book on Allergy 1 5 Copyright 2011 World Allergy Organization • The clinical spectrum of DHR involves various organs, timing and severity. • DHR can be severe, even life threatening, and are associated with significant mortality rates. Drugs may be responsible for up to 20% of fatalities due to anaphylaxis. • DHR have a significant socio-economic impact on both direct costs (management of reactions and hospitalizations) and indirect costs (missed work/school days; alternative drugs). • Diagnostic procedures for DHR should also attempt to identify the underlying mechanisms causing the DHR. • Diagnosis is critical for DHR management and prevention. Selection of an alternative drug and desensitization is necessary in some cases. Insect Allergy • Hymenoptera venom allergy (HVA) is a common global medical problem and refers to subjects who have a sting-induced large local (LL) or systemic allergic reaction (anaphylaxis). A LL reaction is defined as a reaction larger than 10 cm in diameter which lasts over 24 hours in which the signs and symptoms are confined to tissues contiguous with the sting site. Systemic reactions cause generalized signs and symptoms and include a spectrum of manifestations, ranging from mild to life-threatening. Mild systemic reactions may be limited only to the skin and consist of flushing, urticaria, and angioedema. More severe systemic reactions can involve bronchospasm, laryngeal edema, and hypotension. HVA can cause fatal anaphylaxis. • The morbidity rate is underestimated; fatal reactions may not be appropriately recorded, accounting for this underestimation. • The incidence of positive specific IgE antibodies to venom is high in the general population, but only a fraction of such individuals develop a systemic reaction. • Fatal reactions occur in up to 50% of individuals who have no documented history of a previous systemic reaction. • HVA impairs long-term quality of life (QOL) and is the cause of substantial socio-economic problems. • A subject’s QOL is negatively affected when appropriate diagnosis and education are not achieved and when venom immunotherapy (VIT) (a series of injections of the venom to which the subject is allergic and which essentially cures their disease) is not utilized. • HVA can be effectively treated with VIT and appropriate venom therapies. • HVA poses a problem in occupational settings, especially in bee keepers and greenhouse workers. • HVA has important adverse consequences in terms of employment, earning capacity and leisure and sporting activities. • HVA has a substantial adverse financial impact on healthcare costs. Occupational Allergy • Occupational allergic diseases represent an important public health issue due to their high prevalence and their socio-economic burden. • Occupational asthma (OA) contributes significantly to the global burden of asthma, since the condition accounts for approximately 15% of asthma amongst adults. • Allergic contact dermatitis (ACD) is one of the most common occupational diseases. • Occupational allergic diseases remain largely underrecognized by physicians,