Transcript A L L E R G Y A N D A S T H M A M I S E R Y

Allergy, Asthma and Immunotherapy
Give Your Patients Back Their Lives
S545v2
Facts & Figures
• Over 60 million people in the US suffer from allergies
• If you have allergies, you may have undiagnosed asthma or be
at risk for developing it
• Asthma is diagnosed in 7% of the population and is on the rise
• 80% of patients with asthma have allergic symptoms
• More than 20% of children with allergic symptoms develop
asthma
• Allergy and asthma are more common in industrialized nations
• Asthma is the 6th most common primary care diagnosis
How Does Allergy Work?
• The type of antibody responsible for allergy is IgE.
• IgE is thought to have evolved to recognize parasitic infections,
such as intestinal worms.
• Bacterial infections are recognized by another antibody, IgG,
which has a different, non-allergic, response.
• So, to an allergic immune system, a harmless protiean is the
same thing as a parasitic infection.
• This is referred to as a Type I Allergy (IgE-Antibody-Dependent)
– There are other types of allergy (Type II, III, etc), but these have
different mechanisms and are not relevant to our topic.
Type I Allergy Sensitization (Complex View)
•
•
Initial immune exposure
–
Allergen encountered
–
T cells activated (Th2)
–
IgE produced towards allergen
–
Mast cells bind circulating IgE
Subsequent exposure
–
Allergen binds IgE on mast cells
–
Mast cells release chemicals that
cause immune response:
•
Histamine
•
Leukotrienes
•
prostaglandins
symptoms
•
Organ-specific reaction (local)
•
Peripheral reaction (systemic)
The Hygiene Hypothesis – The cause?
•
Based on global population studies, rates of allergy are much lower in
poor countries that lack advanced sanitation and have more parasitic
infections.
•
When advanced sanitation is developed, these infections decline.
•
However, the body’s ability to recognize and respond to these
infections does not disappear. Instead, IgE simply reacts to other
proteins the body is exposed to (pollen, cat hair, etc).
•
This leads to a widespread pattern of unnecessary immune responses
(allergy) in societies that have advanced sanitation.
•
Therefore, rates of allergy and asthma are much higher in modern,
wealthy societies.
What is Asthma
• An inflammatory disease of the airways
• Triggered by many factors including allergens, environment,
infections, and other irritants
• Most common symptoms:
– Wheezing and dry cough
– Increased mucus production
– Bronchospasm and airway constriction
• Severity levels vary and can be measured by degree of
decreased pulmonary function
Diagnosing Asthma Severity
• Mild intermittent asthma: Symptoms rarely occur and only after
above normal levels of activity
• Mild persistent asthma: Symptoms occur <1/day and only
exacerbated by activity
• Moderate persistent asthma: Daily symptoms and routine
activities become difficult. Oral corticosteroids needed.
• Severe persistent asthma: Continual symptoms, must limit
activity and many “attacks” occur. Additional daily treatments
needed.
Krouse, J, et al. OTO – Head & Neck Surgery 2007;136:S75-S106
Differential Diagnosis
• These conditions can be confused with
asthma symptoms and should be considered
during evaluation
– COPD
– Pulmonary fibrosis
– Tumors
– Infections
– GERD
Between 1980 and 1998, reported cases of asthma
doubled in the U.S. The prevalence of asthma is
consistently higher in children.
CDC, Forecasted state-specific estimates of self-reported asthma prevalence – United States, 1998; MMWR 1998;47(47):1022-1025.
The Cost of Asthma
•
In 2007, the average annual medical cost for an asthmatic patient was
~ $1,300 and continues to rise.
•
While only 10-20% of patients have severe asthma, this accounts for
over 50% of all asthma costs.
•
Annual medical costs are 46% higher in patients with associated
asthma and allergic rhinitis.
•
In any given 12-month period there are:
– 14 million lost school days
– 20 million missed work days
– 20 million outpatient visits
– 1.8 million ED visits
– 5,000 deaths
Krouse, J, et al. OTO – Head & Neck Surgery 2007;136:S75-S106
Is Asthma Really Under Control?
• Relying on patient reports could overestimate the
level of control.
• Patients often overestimate their pulmonary function
when compared to peak flow results. This affects
compliance with medication.
• Symptom management often misses underlying
issues like allergies.
• Be Proactive. Don’t wait for symptoms to present
themselves.
Krouse, J, et al. OTO – Head & Neck Surgery 2007;136:S75-S106
Linking Allergies with Asthma
• Allergy is one of the main triggers of asthma and is
often a precursor.
• There is a significant correlation between the severity
of allergic rhinitis and the ability to control asthma.
• Exposure to allergens can cause rapid onset of
bronchospasm.
• Doctors frequently overlook the allergic trigger in
asthmatic patients or the asthmatic potential in
allergic patients.
Vinuya, R. Ann Allergy Asthma Immunol 2002;88(Suppl):8-15
Krouse, J, et al. OTO – Head & Neck Surgery 2007;136:S75-S106
The Unified Airway - Linking Allergies and Asthma
Isolated irritants in one part of the respiratory system have
been shown to cause inflammation in distant parts, suggesting
a common inflammatory pathway.
Inflammation in the
upper respiratory tract
Inflammation in the
lower respiratory tract
Vinuya, R. Ann Allergy Asthma Immunol 2002;88(Suppl):8-15
Ricca, V, et al. J Allergy Clin Immunol 1999;104:54-57
Serrano, C, et al. Arch Bronconeumol 2005;41(10):569-578
Allergens Causing Asthma?
• Chronic allergens can drastically increase the risk of
developing asthma in vulnerable patients:
– Dust Mites
– Molds
– Pets (Hair & Dander)
– Cockroaches
• Allergic responses to these allergens can also be
interpreted as uncontrolled asthma, which masks the
underlying cause and delays adequate treatment.
Vinuya, R. Ann Allergy Asthma Immunol 2002;88(Suppl):8-15
Gaffin, J, & Phipatanakul, W. Curr Opin Allergy Clin Immunol 2009;9(2):128-135
Important Tests for Potential Immunotherapy
Patients
• Allergy
– The patient’s allergic response must be diagnosed as Type I
hypersensitivity (IgE antibody mediated) through skin or in-vitro
testing.
– Skin test results can be used as an immediate educational tool to
illustrate the impact of different allergens to the patient.
• Respiratory
– An objective evaluation of patient lung function establishes a
baseline for monitoring disease progression
– Commonly done with Peak Flow and Spirometry
– Requires patient and staff training to implement effectively
Controlling the Allergy Trigger
• Avoidance
– Can be effective if used in combination with treatment
– However, many allergens are essentially unavoidable
• Symptomatic treatment (e.g. Antihistamines)
– Provides immediate relief
– However, doesn’t change the underlying cause of the symptoms.
– Relief only lasts as long as the patient is compliant.
• Immunotherapy
– Changes the underlying immune response to the allergen
– Provides long-term relief
– May see a positive impact within 3-6 months
Serrano, C, et al. Arch Bronconeumol 2005;41(10):569-578
Immunotherapy and Asthma
• Allergy Immunotherapy (IT) has been shown to
– Reduce allergic rhinitis thus improving asthmatic symptoms
– Reduce the need for asthma medications
– Reduce general inflammation in the airways over time
– Drastically slow or halt the progression of asthmatic disease
• In numerous clinical studies, subjects reported significantly
fewer asthma symptoms and required less asthma medication
than the placebo group.
• Experts found that IT was effective in treating allergic asthma in
71% of patients.
Passalacqua, G, & Durham, S. J Allergy Clin Immunol 2007;119:881-891
Abramson, M, et al. Allergy 1999;54:1022-1041
Ross, R, et al. Clin Ther 2000;22:329-341
Jacobsen, L, et al. Allergy 2007;62:943-948
“Immunotherapy is the only treatment
that influences the basic course of
allergic disease”
World Health Organization (WHO)
Position Paper, 1998
Recommendations of the Allergic Rhinitis and Its Impact
on Asthma (ARIA) Workshop Group
•
Patients with persistent rhinitis should be assessed for the presence of asthma.
•
Patients with persistent asthma should be assessed for the presence of rhinitis.
•
An appropriate therapeutic strategy should combine safe and effective
management of the upper and lower airways.
RHINITIS
ASTHMA
Inhaled
Corticosteroids
Nasal Corticosteroids
Antihistamines
Immunotherapy
Education and Measures to Avoid Exposure to Allergens
Adapted from: Serrano, C, et al. Arch Bronconeumol 2005;41(10):569-578
Refer to An Allergist
• National Asthma Education and Prevention
Program guidelines recommend that patients
who require daily asthma medication be
considered for allergy testing.
• If a patient’s allergies can not be controlled,
and they are a candidate for immunotherapy,
they should be referred to an Allergist.
Platts-Mills, T, et al. Am Fam Physician 2007;76:675-680
Asthma Candidates for Immunotherapy
• The patient’s allergic response is a major component of his/her
asthma symptoms
• There is clear evidence that the patient is exposed to, and
symptomatic towards, unavoidable allergens
• Symptoms are chronic and persistent
• Patient requires daily asthma medications
• Patient is interested in treatment options besides medication
Platts-Mills, T, et al. Am Fam Physician 2007;76:675-680
Immunotherapy Precautions
• IT does not provide immediate improvement
• IT can be dangerous, resulting in anaphylaxis
in some patients
• Patients with uncontrolled asthma should
NOT be given IT since they are more likely to
have severe adverse reactions
Summary
• Asthma is a complex disease, influenced by many
factors
• Since asthma shares a common inflammatory
pathway as allergic rhinitis, with significant
comorbidity, both conditions should be addressed
simultaneously.
• In some asthma patients, immunotherapy may be an
effective treatment option.