World Allergy Organization Guidelines for Prevention of Allergy and Allergic Asthma

Editors

S.G.O. Johansson

Tari Haahtela

WAO Project Co-ordinator

Karen Henley DaviesPrevention of Allergy and Allergic Asthma. World Allergy Organisation Project Report and Guidelines. Eds. SGO Johansson and T Haahtela. Chemical Immunology and Allergy. Editors J Ring et al. Vol. 84, Karger, Basel, 2005.

Prevention, Definitions Primary Prevention: prevention of immunological

sensitization (i.e. development of IgE antibodies)

Secondary Prevention: preventing development of an allergic disease following sensitization

Tertiary Prevention: treatment of allergic diseases and asthma

Measures should benefit all, not harm anyone, not involve unreasonable costs

PAAA ContributorsCarlos Baena Cagnani, Argentina

Patrick Holt, Australia

Charles Naspitz, Brazil

Nan-Shan Zhong, China

Arne Høst, Denmark

Johannes Ring, Germany

Torsten Schäfer, Germany

Ulrich Wahn, Germany

Michal Hemmo-Lotem, Israel

Benjamin Volovitz, Israel

Attilio Boner, Italy

G. Walter Canonica, Italy

Yoji Iikura, Japan

Joseph Odhiambo, Kenya

Innes Asher, New ZealandTadd Clayton, New ZealandMarek L. Kowalski, PolandAlexander Chuchalin, RussiaJoaquin Sastre, SpainMatthias Haus, South AfricaPakit Vichyanond, ThailandElif Dagli, TurkeyAdnan Custovic, UKStephen T. Holgate, UKJohn W. Holloway, UKKatherine Venables, UKJohn Warner, UKAllen Kaplan, USARichard Lockey, USAKewin Weiss, USA

GeneticsCurrent knowledge

The atopic constitution is a major risk factor for the development of IgE-sensitization

Individuals with a family history of atopy have an increased risk of developing allergic diseases

Target organ sensitivity is a familial trait

Environmental Influences on Asthma and Allergy - Current knowledge

Cigarette smoking in pregnancy increases the risk of wheezing in infancy

Environmental Tobacco Smoke aggravates asthma

Allergen avoidance is partially successful (high risk infants)

Some early respiratory infections, e.g. pertussis and RSV, may enhance IgE-sensitization

Relative lack of early microbial exposure may enhance the

development of allergic diseases

Early Immunological InfluencesCurrent knowledge

Allergen specific T-helper cell programming is initiated early in life

and is driven by ubiquitos dietary and inhalant allergens

Early exposure to high levels of dietary allergens results in high zone

tolerance

Exposure to low levels of inhalant allergens triggers low zone

tolerance with weak Th1-like immunity or Th2 polarised response

Predictive and Early DiagnosisCurrent knowledge

Double heredity means a four-fold risk to develop allergies

Single heredity means a two-fold risk

Early signs of atopic eczema, and presence of IgE antibodies to inhalant allergens, are important risk factors for later respiratory allergy

High IgE level in cord blood is specific for subsequent allergic disease but has a low sensitivity

Preventive MeasuresGuidelines

Primary prevention Avoid smoking and Environmental Tobacco Smoke, particularly during

pregnancy and early childhood (B). Remove tobacco smoke from work places (B)

Avoid damp housing conditions (C) and reduce indoor air pollutants (C) Breast-feed exclusively until 4-6 months (B*). No special diet for

lactating mothers (A) Reduce exposure to inhalant allergens in young children at high risk Eliminate sensitizing and highly irritating agents in occupational

environments (C). Implement measures to prevent employee exposure * WHO: exclusive breast-feeding for 6 months in general

Preventive MeasuresGuidelines

Secondary prevention

Treat atopic eczema topically, and possibly with systemic pharmacotherapy to prevent respiratory allergy (D)

Treat upper airways disease (rhinoconjunctivitis, sinusitis) to reduce risk of asthma (D)

In young children sensitized to mites, pets or cockroaches, exposure should be reduced to prevent onset of allergic disease (B)

Remove employees from occupational exposure if they have symptoms caused by occupational allergic sensitization (C)

Preventive MeasuresGuidelines

Tertiary prevention Infants with cow’s milk allergy avoid cow’s milk proteins; if a supplement is

needed, use hypoallergenic formula, if available/affordable, to improve symptom control (B)

Patients with asthma, rhinoconjunctivitis or eczema, who are allergic to indoor allergens, should eliminate or reduce the exposure to improve symptom control and prevent exacerbations (A-B)

Aim pharmacotherapy primarily towards the underlying inflammatory process (A)

Avoid strictly ASA and other non-steroidal anti-inflammatory drugs (NSAID) in patients who are sensitive to them (C)

Preventive MeasuresFurther actions for occupational allergies

Risks of occupational allergy should be monitored and epidemiological information collected by a globally agreed questionnaire

High risk allergy environments should be identified. In atopic employees who work in these environments, detection of sensitization by Skin Prick/Puncture Tests or IgE antibody measurements could prevent development of clinical allergy

General principles of prevention of occupational allergies should be published by national regulatory and advisory authorities

Allergy and Asthma EducationGuidelines

Patient education regarding precipitants of allergic

symptoms, asthma and anaphylaxis is essential.

Guided self-management is the key to optimizing

disease control (A)

School policies on asthma and anaphylaxis

management are essential (D)

Allergy and Asthma EducationFurther actions required

Initiation of an International Coalition for Allergy and Asthma

Prevention. The aims are:

To collect effective programs in a database for all countries

To establish an annual convention on allergy and asthma

prevention, education and applied research

To establish an International Allergy and Asthma Prevention &

Education Promotion Fund

The Costs of Allergy and AsthmaGuideline

Cost of treating allergies and asthma are increasing, switching

from hospital costs to medication costs in developed countries

When considering any intervention, take into account not only

the evidence showing beneficial effect but also the costs

Use the most cost-effective product or measure

Patient Information (Appendix 1)Allergens House dust mite allergen reduction (major

strategies, additional strategies)

Pollen avoidance

Pet allergen avoidance

Cockroach allergen avoidance

Mould allergen avoidance (indoors, outdoors)

Severe reactions, allergic anaphylaxis (schools, work places)

Educational Programs (Appendix 2)

Allergic asthma and rhinitis

Atopic eczema/dermatitis

Severe Reactions, allergic anaphylaxis (schools, work places)

Preventive MeasuresGuidelines

Education

Patient education regarding precipitants of asthma, allergic

symptoms, and especially anaphylaxis is essential. Guided self-

management to prevent, assess and treat symptoms is the key to

optimizing disease control (A)

School policies on asthma and anaphylaxis management are useful

(D)