Common Allergic and Immunologic Diseases


 

Asthma

People with asthma have difficulty breathing due to temporary narrowing of the airways in their lungs.  The symptoms include wheezing, chest tightness, and coughing. Coughing, especially at night time, or exercise intolerance may be the only manifestation at the beginning.  Like in other allergic diseases, the incidence of asthma has been on the rise (why? - see the discussion under separate topic) in the USA and other developed countries of the world. In the USA, 7 -10% of the population have experienced asthma and in Australia ~25% have!! Children growing in developing countries and farms are reported to have fewer incidences. It affects all ages, ethnicities, and even the physically fit. One out of every five 1998 U.S. winter Olympic athletes has reported using asthma medicines.  There is some evidence suggesting that exposures to the virus, other microbes, and animals early in life may prevent the disease. However, later in life, the same exposures may provoke asthma attacks. Although we cannot cure the disease, new medicines have been reported to be much more effective in controlling the disease

Causes: In children, allergies are the predominant cause, but, in adults, allergies are demonstrated in only half of the patients. Allergic tendencies are inherited; maternal transmission rate is ~40%, paternal 30%, and 60-70% from both parents. Research shows that there are many genes involved.  Some combination of genes probably produces more potent allergic manifestation. Non-allergic causes of asthma are not known. Whether allergic or non-allergic, asthma attacks can be triggered by irritants including smoke, fumes, wind, emotion, and physical exertion.

Evaluation:

  • History, family history, environmental assessment, physical exam
  • Allergen skin test
  • Lab tests including RAST
  • Spirometry:
    • FEV1 (forced expiratory volume at one second): Asthmatics cannot blow out air due to the narrowed airway. Therefore, the amount of air one blows out in one second gives a very good measure of asthma severity. When treated with bronchodilator such as albuterol, FEV1 increases at least 12 % in untreated asthmatics.
    • FEV1/FVC: The ratio of FEV1 to functional vital capacity (which approximates lung volume) gives a better picture of lung obstruction. Less than 80% is considered significant.
  • Peak Flow meter: Peak flow (fastest speed with which you blow) is an easy way of measuring lung function since it does not require a spirometer. It approximates FEV1.
  • Nitric oxide measurement: Asthmatics exhale more nitric oxide than non-asthmatics. Studies show that NO measurement may be used as a tool to adjust asthma medications. This test is offered at Dr. Songs office. Some insurance companies do not reimburse the cost.

It is important to realize the value is only as good as the patient’s effort. Therefore the results need to be interpreted with this in mind.

Prognosis
For most adults, the disease activity, unfortunately, tends to stay the same or may get progressively worse. Some children grow out of asthma, but most allergic children don’t.  One study (Martinez, Tuscon) reported that 2-3 yr old children have a 75% chance of continuing to wheeze at the age of 6-13 years when they have met the following criteria (2 major and 1 minor). 

  • Major criteria: parental asthma, eczema
  • Minor criteria: allergic rhinitis (hay fever), wheezing apart from cold, eosinophilia >4%

Another study showed that if a child is wheezing and has positive reactions to an 
allergy skin test at the age of  6, there is a greater than 85% chance of wheezing at the age of 11 years.

Treatment:
Depending on the severity and the causes of asthma, the patient and doctor need to develop a comprehensive treatment plan including the components listed below.  Some patients need to be on controller medicines all the time.

  • Avoidance of triggers
    • Allergens (patient specific): mites, pollens, animal danders, foods, etc.
    • Irritants (patient non-specific): polluted air, air temperature change, draft, wind, fog, laughter, etc.
    • Stress: emotional or physical
  • Drugs: Combination of drugs are used in accordance with the disease severity.
    • Rescue medicines: Albuterol (Proventil, Ventolin), Xopenex, Atrovent
    • Controllers: Inhaled cortico-steroids, anti-leukotriens such as Singulair & Zyflo, Xolair
    • Combination of the two
  • Allergen immunotherapy (allergen injections): Early intervention may modify or eliminate the disease.  Discussed under a separate topic.


Drugs

    • Rescue meds:
      • SABA(short-acting beta-agonist): works in minutes and is associated with jitteriness and heart palpitation. Can be delivered by an inhaler (MDI) or a nebulizer. Learn to use the inhaler properly. A spacer (such as Aerochamber) is necessary for children. A nebulizer is primarily used for infants and young children, especially when asthma is severe since more medicine can be delivered that way. Use a Pari nebulizer because it delivers the smallest particle size.  Only a portion of inhaled medicines end up in the lungs. If you use spacers, the number of aerosol deposits may increase.
        • Albuterol (Proventil, Ventolin): increases windpipe caliber by relaxing smooth muscles through adrenergic pathway
        • Xopenex (Levalbuterol): possibly, more potent and fewer side effects than albuterol.
        • Atrovent (Ipratropium Bromide): anticholinergic; antagonizes bronchial constriction by blocking cholinergic input. Minimal cardiac effect
        • Spiriva (Tiotropium): Long-acting anticholinergic
        • Combivent (Ipratropium + Albuterol)
    • Controller meds:
      • These medicines are used for long-term control of the disease. Most studies show that regular use of these medications decreases the symptom fluctuations, emergency room visits, and hospitalization.  For milder asthmatics, the controller medicine may be used at the beginning of an upper respiratory infection to abort the asthma exacerbation.
        • Inhaled cortico-steroids (ICS): Flovent, Pulmicort, Asmanex
          • Most studies show that even the prolonged use of them is not associated with any major side effects. Some studies demonstrated that the growth rate of children'may be decreased if inhaled steroid were to be used regularly for a long time (loss of 0.8cm in adult height).
          • Most common side effects: hoarse voice and oral thrush which go away when the medicine is stopped.
          • Flovent comes in 3 different potencies: 220, 110, 44.  Pulmicort comes either as an inhaler or respules (0.25 mg, 0.5 mg) for a nebulizer.  Currently, Pulmicort respule is the only inhaled steroid available for infants.
        • LABA (long-acting beta-agonist); Serevent, Foridil
          • Gives broncho-dilating effect for 8-12 hrs.
          • Sole use of the drug is not recommended due to the potential risk of death reported especially among black asthmatics (BLACK BOX WARNING).
        • Combination of steriod and LANA
          • When these medicines are combined, the effects are synergistic and the risk associated with the sole use of LABA decreases.
          • Advair is an inhaler which combines Flovent and Serevent. Comes in 3 different strengths; 500/50, 250/50, 100/50. Approved for asthmatics aged 4 years and above. DO NOT TAKE MORE THAN TWICE A DAY because the effect is cumulative and can become toxic.
          • Symbicort is an inhaler which combines Pulmicort (budesonide) and Oxis (formoterol). Approved for use for asthmatics aged 12 years and above. The dose can be adjusted.
          • Dulera is an inhaler which combines mometasone and formoterol. Approved for patients over 12 years of age. The dose can be adjusted.
        • Leukotriene inhibitors
          • Singulair is a leukotriene receptor antagonist (LTRA ) and is used most widely among its class.
          • Available in 3 strengths: 10 mg for >14yrs of age, 5 mg for 6-14 yrs, and 4 mg for 2-5 years of age.
          • Not as effective as steroid inhalers, but is more convenient to use.
          • Recommended as a solo medicine for mild asthma and in combination with a steroid inhaler for moderate to severe asthma.
          • It has a steroid-sparing effect.
          • Minimal side effects. Some patients report sleep disturbance, including nightmares.
        • Oral steroids: used only when there are severe symptoms. They are used for only for a few to several days (burst) to minimize the long-term side effects of weight gain, bone loss, cataracts, GI disturbances, immune suppression, etc. The most common short-term side effect is mood swings.
        • Anti-IgE (Xolair) may be used as an adjunctive therapy for severe allergic asthmatics. It is supposed to mop up all of the IgE molecules produced and theoretically eliminate allergic symptoms. Some patients respond dramatically and others improve only minimally. It has to be given every 2  or 4 weeks; the use is restricted to severe asthma and needs prior authorization. Lately, there were reports of delayed anaphylaxis (0.1% of patients).


The standard guidelines for pharmacotherapy are published every 5 years by then AEPP (National Asthma Education Prevention Program). The current one is from 2002 and the 2007 version is about to be released.

The 2007 guidelines recommend 6 different steps of treatment, depending on the degree of severity, control, and responsiveness.  Listed below is the summary, which I will follow in general after a full discussion with patients.

 

Day Sxs

Night Sxs

Peak Flow

Controller Meds

Rescue Meds

Intermittent

< 2 x /wk

< 2 x / month

>80%

 

PRN

Mild persistent

> 2 x / wk

> 2 x / month

> 80%

Step 2,

PRN

Moderate persistent

daily

> 1 x / wk

>60%,  <80%

Step 3

PRN

Severe peristent

constant

frequent

<60%

Step 4 or 5  or 6

PRN


Normal peak flow rate can be estimated by 30 + 30 x age  from 5 to 16 yrs of age.

Step 1: SABA
Step 2: low dose ICS or LTRA
Step 3: medium dose ICS or low dose comb or low dose steroid inhaler + LTRA
Step 4: medium combo or med ICS+ LTRA
Step 5: high combo,  Xolair
Step 6; high combo + oral steroid, Xolair

If the symptoms are well controlled for 3 months, consider stepping down or lowering ICS by 25-30% every 3 months until the lowest dose is achieved.

If the symptoms are not controlled, one needs to step up.

A written step-wise written plan, listing medications to be added based on peak flow and symptom parameters, should be prepared for patients. It is essential to work with the doctor on a regular basis. For an acute episode, know when, where and whom to call, and do not delay!


Peak Flow

Condition

Symptoms

Treatment

80-100%

GREEN: Safe

Easy breathing
No cough

Controller

60-79%

YELLOW: Caution

Cough, wheezing, tight chest

Controller
Rescue medicine

<60%

RED: Danger

As above
Meds not working
Hard to breathe

Above meds
Oral Meds
Call MD

Some patients wheeze only with physical exertion, typically 5-10 minutes into exercise. The symptoms can be controlled with an albuterol inhalation 10-15 minutes before exercise. Other preventive programs may include taking Singulair or Advair 100/50 on a daily basis if one engages in sports every day.

Conditions Treated and Services Offered

What we treat and what we do

Location
Song Institute of Allergy, Asthma and Immunology
3113 N. Sepulveda Blvd , Suite A
South Bay

Manhattan Beach, CA 90266
Phone: 310-981-3236
Fax: (310) 802-8031
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310-981-3236