Allergy Notes: 08/2011

Low-dose fluticasone is less expensive and more effective than montelukast in children with asthma

This study compared the cost-effectiveness of 2 commonly used asthma controllers, fluticasone and montelukast in a randomized, controlled, multicenter clinical trial in children with mild-to-moderate persistent asthma.

Effectiveness measures included:

- number of asthma-control days
- percentage of participants with an increase over baseline of FEV(1) of 12% or greater
- number of exacerbations

For all cost-effectiveness measures studied, fluticasone cost less and was more effective than montelukast. For example, fluticasone treatment cost $430 less and resulted in 40 more asthma-control days during the 48-week study period.

For children with mild-to-moderate persistent asthma, low-dose fluticasone had lower cost and higher effectiveness compared with montelukast, especially in those with more airway inflammation (indicated by increased eNO and more responsivity to methacholine).

However, montelukast will be generic in the U.S. in 2012 and this will definitely affect its cost-effectiveness.

References:

Cost-effectiveness analysis of fluticasone versus montelukast in children with mild-to-moderate persistent asthma in the Pediatric Asthma Controller Trial. Wang L, Hollenbeak CS, Mauger DT, Zeiger RS, Paul IM, Sorkness CA, Lemanske RF Jr, Martinez FD, Strunk RC, Szefler SJ, Taussig LM; Childhood Asthma Research and Education Network of the National Heart, Lung, and Blood Institute. J Allergy Clin Immunol. 2011 Jan;127(1):161-166.e1.

Montelukast failure index that may be helpful in predicting response in patients with asthma http://goo.gl/AzRPF

Image source: Montelukast, Wikipedia, public domain.

Icatibant subcutaneous injection (Firazyr) can be self-administered by patients upon recognition of HAE attack

Approximately 30,000 individuals in the U.S. have Hereditary Angioedema (HAE).

Icatibant, a bradykinin B2 receptor antagonist, is supplied in a prefilled syringe. Itc can be stored at room temperature (up to 77°F) for immediate use.

New therapies for hereditary angioedema (HAE) (click to enlarge the image).

Two other agents were approved by the FDA in 2009 for treatment of HAE attacks:

- plasma-derived C1-esterase inhibitor concentrate for injection (Berinert) for HAE-related acute abdominal attacks and facial swelling. HAE patients can self-administer Berinert C1-INH by IV infusion - FDA, 2012.

- ecallantide subcutaneous injection (Kalbitor) for treatment of HAE attacks

Cinryze (C1-esterase inhibitor concentrate) is approved for prophylaxis of HAE, not for treatment of acute attacks.

This is a good summary from Medscape's Atopic Topics blog:

Unlike Ecallantide which is only approved for administration in a supervised setting (due to risk of hypersensitivity reaction), Firazyr is approved for use by the patient.

Screening for HAE is a simple process - C4 is always low in HAE (unless the patient is already treated for the disease). A normal C4 therefore rules it out. If C4 is low, a quantitative AND qualitative C1 inhibitor levels should be checked

References:

FDA Approves New Drug for Hereditary Angioedema. Medscape, 2011.

HAE patients can self-administer Berinert C1-INH by IV infusion - FDA, 2012.

Exercise-induced Asthma Success Story - ACAAI video

This success story follows 10-year-old Ben as he seeks exercise induced asthma relief from Allergists certified by the American College of Allergy, Asthma and Immunology.

"Find the most common food allergens" toy set

I call this "Find the most common food allergens" toy set, available at IKEA (shown above).

From a clinical perspective, 8-9 top allergens account for 90% of food allergies:

8 top allergens account for 90 percent of food allergies. Specific IgE levels (sIgE) that predict the likelihood of passing an oral food challenge are shown in the figure. (click to enlarge the image).

Comparison of diagnostic methods for peanut, egg, and milk allergy - skin prick test (SPT) vs. specific IgE (sIgE) (click to see the spreadsheet). Sensitivity of blood allergy testing is 25-30% lower than that of skin testing, based on comparative studies (CCJM 2011).

Available at IKEA:

DUKTIG, 15-piece breakfast set, $7.99, Care instructions: Machine wash, warm 104 F (40°C), delicate cycle. Do not bleach. Tumble dry, low temperature. Do not iron. Do not dryclean.

DUKTIG, 9-piece fruit basket set, $7.99

DUKTIG, 14-piece vegetables set, $7.99 (shown above).

Related:
Mind Maps: Food Allergy

Half Dose Honeybee Venom Immunotherapy (50 mcg) May Be Effective in Children

Honeybee venom immunotherapy with 50 micrograms, half the recommended dose, may prevent systemic reactions in children.

This dose prevented systemic reactions in 86% (38/44) of children and 94% of stings after honeybee venom immunotherapy.

"Comparing our results with patients with honeybee venom allergy who received 100 micrograms, the rates of protection with 50-microgram venom immunotherapy for field stings appear similar", said the researchers.

As many as 1 in 100 children may have systemic allergic reactions to insect stings, and about 40% of children who have moderate-to-severe reactions need ongoing venom immunotherapy.

References:

Lower Dose of Honeybee Venom Immunotherapy Effective in Children. Medscape.
Honeybee venom immunotherapy in children using a 50-μg maintenance dose. JACI, 2011.
Honeybee immunotherapy is less safe and less effective than for other flying Hymenoptera http://goo.gl/RgAjj
Image source: Wikipedia 1, 2, GNU Free Documentation License.

Comments from Twitter:

@allergistmommy (Sakina Bajowala, M.D): Good news- 1cc IT is a lot for a skinny little arm.

Allergy to pizza: uncommon, multifaceted and difficult to diagnose

The involvement of the Italian "pizza" in food allergy is uncommon. This simple Italian dish consists of a breadlike crust covered by a spiced preparation of cheese and tomatoes and baked.

In the beginning, pizza was the food of the poor, but was made with natural foods, but nowadays has been enriched by a number of ingredients and flavourings, thus multiplying the risk of allergic reactions.

I recommend the following approach:

- careful review of the list of ingredients and skin prick test and/or specific IgE test (blood test) with the suspected ingredients
- prick-puncture test with the food product
- open label food challenge, if the risk of anaphylaxis is low

References:

Allergy to pizza: an uncommon and multifaceted allergy. Cantani A. Eur Rev Med Pharmacol Sci. 1999 Sep-Oct;3(5):235-6.
Presumed pizza allergy disproven. Madhu B. Narra, MD, MS. WAO Clinical Allergy Tips, 2009.
Allergy to pasta sauce

Abdominal ultrasonography useful as early diagnostic tool for acute abdominal attack in hereditary angioedema (HAE)

Hereditary angioedema (HAE) is caused by the deficiency of functional C1 inhibitor. Symptoms of this disease include:

- cutaneous angioedema
- abdominal pain
- laryngeal edema

59 adult patients with HAE were included in this study - 55 had any symptom due to HAE (abdominal location, 78%); 4 patients were asymptomatic.

In 11 cases, ultrasonography was performed during acute attacks. Ascites and intestinal wall swelling were found in 7, and thus diagnosis was confirmed.

C1 protein, showing subunits C1r, C1s, and the C1q tails. Image source: Wikipedia. Hereditary angioedema (HAE) is an autosomal dominant condition associated with episodic attacks of nonpitting edema. Patients with HAE have low levels of C1 inhibitor (a serine protease inhibitor). Edema is caused by unregulated generation of bradykinin.

The authors concluded that abdominal ultrasonography has been proved useful as an early tool for diagnosing the adverse effects of therapy and for confirming diagnosis in the case of an acute abdominal attack.

References:
Usefulness of abdominal ultrasonography in the follow-up of patients with hereditary C1-inhibitor deficiency. Pedrosa M, Caballero T, Gómez-Traseira C, Olveira A, López-Serrano C. Ann Allergy Asthma Immunol. 2009 Jun;102(6):483-6.

Children with uncontrolled allergic rhinitis "learn" to avoid fruits and vegetables

Some studies suggest that fruit and vegetable consumption reduces the risk of allergic disease in children, but results are conflicting.

This Swedish study investigated the association between current fruit or vegetable intake and allergic disease in 2,000 8-year-old children.

Allergen-specific IgE levels against food and inhalant allergens were obtained at age 8 years.

An inverse relation was observed between total fruit consumption and rhinitis (odds ratio, highest vs lowest quartile, 0.62). No association was observed for total vegetable intake.

In analyses of individual foods, intake of apples/pears and carrots was inversely associated with rhinitis, asthma, and atopic sensitization.

50% of children with rhinitis were sensitized against birch pollen, which may cross-react with apples and carrots.

After exclusion of children who reported food-related allergic symptoms, most of the observed associations became nonsignificant.

On the surface, this sudy confirmed the inverse associations between fruit intake and allergic disease in children. However, disease-related modification of consumption contributed to this association - children with uncontrolled allergic rhinitis simply "learn" to avoid fruits and vegetables due to cross-reactivity observed in pollen-allergy syndrome (oral allergy syndrome).

Cross-reactivity in Pollen-Food Allergy Syndrome (PFAS) or Oral Allergy Syndrome (OAS) (click to enlarge the image).

Which allergen cross-reacts with Bet v1 (birch)?

(A) Ara h1 (peanut)

(B) Mal d 1 (apple)

(D) Bos d (milk)

(E) Gal d (egg)

(F) Hev b2 (latex)

Answer: B, apple. Pollen sensitizations linked to food allergies was first reported with birch pollen and apples 50 years ago.

References:

Fruit and vegetable consumption in relation to allergy: Disease-related modification of consumption? Rosenlund H, Kull I, Pershagen G, Wolk A, Wickman M, Bergström A. J Allergy Clin Immunol. 2011 Jan 6.

Image source: Head and neck. Wikipedia, public domain.

Comments from Twitter:

@Deb_acle: interesting re allergic rhinitis...most ppl noting the correlation would start forcing those kids to eat more offending fruit.

@DrVes: Correct, that's why it's important to have oral allergy syndrome on the differential diagnosis list.

"Easy" Button

Staples' Easy button, $5.95. I sometimes use this to reassure pediatric patients that the new skin test devices (ComforTen, etc.) are virtually painless and provide quick and accurate results, with no needles or blood draw. They are happy to hear "That was easy!" after the procedure.

"Staples Foundation for Learning" will donate proceeds of the product sales, up to $1 million, to Boys & Girls Club of America (2 AAA batteries included).

Allergy to Insulin Products May Occur in 2% of Patients

Insulin-related allergic reactions are rare (2%) but are very important because insulin is a life-saving medications for many patients.

Historical perspective

- The first insulin reaction was reported in 1922 - a callus at the injection site of insufficiently purified bovine insulin (from cow).

- Porcine insulin is less allergenic than bovine insulin.

- Recombinant insulin has the same amino sequence as human insulin and led to a large decrease in adverse reactions.

Insulin itself may not be the allergen

Prevalence of allergic reactions to insulin products is 2% but less than 30% of these are related to the insulin itself. Reactions occur due to the preservatives added to insulin such as zinc, protamine, and meta-cresol.

Types of allergic reactions

Allergic reactions can be:

- type I or IgE-mediated - most common and can, rarely, cause anaphylaxis
- type III or Arthus
- type IV or delayed-type hypersensitivity reactions occur after a delay of several days

Investigations include:

- skin prick testing
- patch testing
- intradermal testing
- skin biopsy

Desensitization protocol for insulin allergy

A negative skin test would be helpful in the evaluation of an immediate hypersensitivity reaction to insulin. Unfortunately, a positive skin test is not helpful because approximately 40% of patients on insulin therapy can have a positive response in the absence of clinical allergy.

IgE and IgG to insulin also play a diagnostic role in various protocols but have no definitive diagnostic significance.

This is a desensitization protocol for insulin allergy from the textbook, "Patterson's Allergic Disease," edition 6, 2002, edited by Grammer and Greenberger, pages 360-2:

References:

Insulin allergy. Mohammad K. Ghazavi, MD, Graham A. Johnston, MBChB, FRCP. Clinics in Dermatology, Volume 29, Issue 3, Pages 300-305 (May 2011).

Possible insulin allergy as manifested by pruritus only. AAAAI.

Image source: Wikipedia, public domain.

20% of patients presenting to the ED with food allergic reactions are admitted

This study from the Massachusetts General Hospital included a medical record review of 1,000 patients that were evaluated at the ED for food-related allergic reactions during 5 years (ICD codes 693.1, 995.0, 995.1, 995.3, 995.7, 995.60-995.69, 558.3, 692.5, and 708.X).

80% of patients were discharged from the ED.

3 factors were associated with a higher likelihood of hospital admission:

- symptoms of food-related anaphylaxis (odds ratio [OR], 2.31)
- pre-ED epinephrine treatment (OR, 6.65)
- epinephrine treatment within 1 hour of ED triage (OR, 3.78)

Patients with food-related allergic reactions triggered by shellfish were less likely to be admitted to the hospital (OR, 0.23).

Most patients presenting to the ED with food-related allergic reactions are discharged.

8 top allergens account for 90 percent of food allergies. Specific IgE levels (sIgE) that predict the likelihood of passing an oral food challenge are shown in the figure. (click to enlarge the image).

References:

Predictors of hospital admission for food-related allergic reactions that present to the emergency department. Banerji A, Rudders SA, Corel B, Garth AP, Clark S, Camargo CA Jr. Ann Allergy Asthma Immunol. 2011 Jan;106(1):42-8.

Elderly asthmatic patients have worse disease control compared with young adult asthmatics

2 million U.S. citizens older than 65 years have asthma. This study from Detroit, Michigan compared asthma control in elderly (≥65 years old) and young adult (18-64 years old) populations.

Elderly patients with asthma had a lower income, were less educated, were more obese, were more insured, had less indoor exposure, and were more likely to be former smokers.

They were less educated about asthma attack interventions and asthma action plans.

Elderly patients had worse control of asthma based on short-term measures (daytime symptoms in the previous month) [odds ratio (OR), 1.7], and long-term measures (activity limitation in the previous year [OR, 1.5].

References:

Effect of age on asthma control: results from the National Asthma Survey. Talreja N, Baptist AP.
Ann Allergy Asthma Immunol. 2011 Jan;106(1):24-9.

Image source: OpenClipart.org, public domain.

Each 1% increase in out-of-pocket money spent on asthma drugs linked to 14% increase in exacerbations

Less than 25% of asthmatic children are well controlled. This retrospective study of 490 children from Canada attempted to identify factors associated with asthma exacerbation related to health status, socioeconomic status (SES), and drug insurance.

Factors associated with asthma exacerbations:

- younger age

- previous emergency visits

- nebulizer use

- pet ownership

- receipt of asthma education but not an action plan

- food, drug, or insect allergies

Children with high income adequacy had 28% fewer exacerbations than did children with low income adequacy.

In the subgroup with drug insurance, girls had 26% fewer exacerbations than did boys. Children with food, drug, or insect allergies had 52% more exacerbations than did children without allergies.

Every percentage increase in the proportion of income spent out-of-pocket on asthma medications was associated with a 14% increase in exacerbations.

The diagram above shows the cost of different asthma Inhalers (click to enlarge the image).

References:

Relationship of asthma management, socioeconomic status, and medication insurance characteristics to exacerbation frequency in children with asthma. Ungar WJ, Paterson JM, Gomes T, Bikangaga P, Gold M, To T, Kozyrskyj AL. Ann Allergy Asthma Immunol. 2011 Jan;106(1):17-23.

Shift-and-persist strategy (reframing stressors positively, optimism) protects low-SES children with asthma. JACI, 2011.

Hypersensitivity reactions to systemic corticosteroids have an incidence of 0.3%

Contact allergy to topical corticosteroids should be considered in all patients who do not respond to, or are made worse by, the use of topical steroids. The incidence of steroid allergy in such patients is reported as 9-22% in adult patients and in 25% of children.

Topical steroid allergy is often undiagnosed for a long time in patients with a history of dermatologic conditions and steroid use.

Although rare, both immediate and delayed-type hypersensitivity reactions have been reported to systemic corticosteroids with an incidence of 0.3%. Reported reactions range from localized eczematous eruptions to systemic reactions, anaphylaxis, and even death.

Delayed reactions to systemic steroids (PO or IV) may present as a generalized dermatitis, an exanthematous eruption, or occasionally, with blistering or purpura.

References:

Effective prescribing in steroid allergy: Controversies and cross-reactions. Clinics in Dermatology, Volume 29, Issue 3, Pages 287-294 (May 2011).
Image source: Amazon.com. Used for illustration only. Not a suggestion to buy any product.

Penicillin skin testing in management of penicillin allergy

This Mayo Clinic meta-analysis reviewed the role of penicillin skin testing in the evaluation and management of penicillin allergy mediated by IgE.

Major determinant

The major determinant (benzylpenicillin polylysine) detects the greatest number of penicillin allergic patients during skin testing.

Minor determinants

The minor determinants of penicillin increase the sensitivity of penicillin skin testing.

Penicillin skin testing to the major and minor determinants have a negative predictive value of 97% to 99%. The incidence of systemic adverse reaction to penicillin skin testing is less than 1%.

A detailed history of the prior reaction to penicillin is an integral part of the evaluation, but it is not accurate in predicting a positive penicillin skin test result.

Negative penicillin skin test

A patient with a negative penicillin skin test result to the major and minor determinants is at a low risk of an immediate-type hypersensitivity reaction to penicillin.

Positive penicillin skin test - what to do?

Patients with a positive skin test result should undergo desensitization to penicillin or an alternative antibiotic should be considered.

Manifestations of beta-lactams hypersensitivity: MAUS (click to enlarge the images).

Mnemonics for penicillin allergy skin testing

Major penicillin determinant test detects

Majority of patients with penicillin allergy

Minor determinant test

Minorizes the risk

References:

Penicillin skin testing in the evaluation and management of penicillin allergy. Fox S, Park MA. Ann Allergy Asthma Immunol. 2011 Jan;106(1):1-7. Epub 2010 Jul 3.

Diagnosis of Immediate Hypersensitivity to β-Lactam Antibiotics Can Be Made Safely with Current Approaches. Int Arch Allergy Immunol. 2011 Nov 1;157(3):311-317.

Image source: Penicillin nucleus, Wikipedia, GNU Free Documentation License.

Chinese Herbal Product (Xiao-Feng-San) Provides Symptom Relief in Refractory Atopic Dermatitis

Severe and widespread atopic dermatitis often fails to respond adequately to topical steroids and oral antihistamines and requires immunomodulatory drugs which, although effective, may have undesirable long-term effects.

This prospective, randomized, double-blind, placebo-controlled trial included 71 patients with severe intractable atopic dermatitis who were given an 8-week treatment with oral Xiao-Feng-San (XFS; 47 patients).

The decrease in the lesion score in the treatment group at 8 weeks was significantly greater than that of the placebo group (79.7 vs. 13.5, p less than 0.001).

Patients reported no side effects from treatment, although some commented on the unpalatability of the medication.

This study from Taiwan suggest that the traditional Chinese herbal medicine XFS may be an alternative choice of therapy for severe, refractory atopic dermatitis.

References:

The Efficacy and Safety of a Chinese Herbal Product (Xiao-Feng-San) for the Treatment of Refractory Atopic Dermatitis: A Randomized, Double-Blind, Placebo-Controlled Trial.
Cheng HM, Chiang LC, Jan YM, Chen GW, Li TC. Int Arch Allergy Immunol. 2010 Dec 22;155(2):141-148.

No Chinese manufacturer has successfully registered herbal medicinal products in the EU - all will be banned in May 2011. The Lancet, 2011.
The quest to find the "magic" Chinese herbal formula continues: Danggui Buxue Tang helps asthmatic MICE http://goo.gl/Bdfle

Image source: Wikipedia, public domain.

House dust mite induces pulmonary T helper 2 cytokine production (in mice)

Inhaled house dust mite (HDM) results in T-helper (TH) 2 type pathology in unsensitized mice. It also induces airway hyperreactivity and airway remodelling.

In this study, mice were exposed to soluble HDM extract for 3 weeks.

Th2 cytokines were increased in bronchoalveolar lavage (BAL) and lung after HDM challenge. The levels of cytokines and chemokines correlated with the influx of eosinophils and Th2 cells. Production of key cytokines such as IL-4, IL-5 and IL-13 preceded the increase in airways resistance.

The study authors concluded that inhaled HDM challenge induces a classical Th2 inflammatory mediator profile in the BAL and lung.

House dust mite sensitization in toddlers predicts wheeze at age 12 years (JACI, 2011).

References:

Inhaled house dust mite induces pulmonary T helper 2 cytokine production. L. G. Gregory et al. Clinical & Experimental Allergy, 06/2009.

Millions suffer 'home fever' as allergy epidemic begins to bite - dust mites account for 58% of household allergies. The Independent, 2011.

How do we know when peanut and tree nut allergies have resolved?

Peanut (PN) and tree nut (TN) allergies cause 50% of all deaths from food-related anaphylaxis

Over the last two decades, the prevalence of peanut and tree nut allergy has increased throughout the Western world. Adverse reactions to these foods account for over 50% of all deaths resulting from food-related anaphylaxis. Until recently, evidence suggested that all peanut and tree nut allergy were permanent. It is now known that about 20% and 10%, respectively, of young patients outgrow peanut and tree nut allergies.

Markers of tolerance

Achieving tolerance is associated with:

- increasing circulating T regulatory cells
- reduced production of allergen-specific IgE

Regulatory T cells - 6 groups have been described as of year 2010 (click to enlarge the image).

Clinical predictors of tolerance

However, reliable predictors of resolution are not yet available. Physicians try to make a correlation between skin test wheal size and allergen-specific IgE, at the time of diagnosis and likelihood of resolution.

Resolution of peanut or tree nut allergy cannot be determined conclusively by either allergen-specific IgE analysis or by skin prick testing.

Oral food challenge is the gold standard for determining resolution of food allergy. Food challenges should only be undertaken in a clinical setting fully equipped to deal with a potential severe adverse reaction.

8 top allergens account for 90 percent of food allergies. Specific IgE levels (sIgE) that predict the likelihood of passing an oral food challenge are shown in the figure. (click to enlarge the image).

8% of peanut (PN) allergy recurs after resolution

8% of patients who outgrow peanut allergy may suffer a recurrence, but recurrent tree nut allergy has not been reported to date.

Therapy is still only experimental

Induction of tolerance through oral immunotherapy (OIT) or sublingual immunotherapy (SLIT) is now studied, but remains experimental. Studies have reported short-term desensitization to peanut, but ongoing follow-up will determine if tolerance is achieved long term.

References:

How do we know when peanut and tree nut allergy have resolved, and how do we keep it resolved? Clinical & Experimental Allergy, 2010.

Basophil Activation Test (BAT) Helps Predict Safety of Oral Challenge in Milk Allergy http://goo.gl/nDAM

Peanut Allergy: An Evolving Clinical Challenge (review), 2011.

Impaired sense of smell in hereditary angioedema

Hereditary angioedema (HAE) is an autosomal-dominant disorder resulting from C1-inhibitor (C1INH) deficiency. Smell impairments were found in patients affected with systemic lupus erythematosus (SLE), that, similarly to HAE, is characterized by the activation of the classical complement pathway with C4 consumption.

30 patients with HAE were evaluated for olfactory functions using the 3-stages Sniffin'-Sticks kit: threshold, discrimination, and identification (TDI scores).

A decrease in olfactory function was found in HAE patients. Anosmia was present only in patients with HAE (3%) who also exhibited more frequently hyposmia (53% vs 3% for controls).

Complement levels were reduced in HAE.

Impaired sense of smell was found in patients with HAE. The reduction in olfactory function in these cases correlated with complement C4 and CH50 levels.

References:

Perricone C, Agmon-Levin N, Shoenfeld N, de Carolis C, Guarino MD, Gigliucci G, Milana I, Novelli L, Valesini G, Perricone R, Shoenfeld Y. Evidence of impaired sense of smell in hereditary angioedema. Allergy 2010; DOI: 10.1111/j.1398-9995.2010.02453.x.

Image source: Wikipedia, a Creative Commons license.

Desensitization protocol for insulin allergy

A negative skin test would be helpful in the evaluation of an immediate hypersensitivity reaction to insulin. Unfortunately, a positive skin test is not helpful because approximately 40% of patients on insulin therapy can have a positive response in the absence of clinical allergy.

IgE and IgG to insulin also play a diagnostic role in various protocols but have no definitive diagnostic significance.

This is a desensitization protocol for insulin allergy from the textbook, "Patterson's Allergic Disease," edition 6, 2002, edited by Grammer and Greenberger, pages 360-2:

Related reading:

Possible insulin allergy as manifested by pruritus only. AAAAI.

Vitamins A, D, E, zinc, fruits, vegetables, and Mediterranean diet may prevent asthma

Epidemiologic studies suggest that deficiencies of the nutrients selenium; zinc; vitamins A, C, D, and E; and low fruit and vegetable intake may be associated with the development of asthma and allergic disorders.

This meta-analysis included 62 reports. However, there were no randomized controlled trials.

Serum vitamin A was lower in children with asthma (odds ratio [OR], 0.25).

High maternal dietary vitamin D and E intakes during pregnancy were protective for the development of wheezing outcomes (OR, 0.56, and OR, 0.68, respectively).

Mediterranean diet was protective for persistent wheeze (OR, 0.22) and atopy (OR, 0.55).

In general, most fruit and vegetable studies reported beneficial associations with asthma and allergic outcomes.

The available epidemiologic evidence is weak but nonetheless supportive with respect to vitamins A, D, and E; zinc; fruits and vegetables; and a Mediterranean diet for the prevention of asthma. Experimental studies of these exposures are now warranted.

References:
Nutrients and foods for the primary prevention of asthma and allergy: Systematic review and meta-analysis. Nurmatov U, Devereux G, Sheikh A. J Allergy Clin Immunol. 2010 Dec 23.

Allergy Notes