Difficult to treat eczema: a review of medications

Sometimes moisturizers and steroid creams aren’t enough. Many patients with severe eczema (atopic dermatitis, AD) require oral medications to keep their skin clear and itching under control. A recent article out of Amsterdam and Germany, reviewed the risks and benefits of several systemic therapies*. Here are the recommendations:

  • Cyclosporin A: first-line short term treatment option for moderate to severe AD. Higher doses (5 mg/kg/day) lead to a more rapid response and higher efficacy.
  • Azathioprine: second-line treatment option.
  • Methotrexate: third-line treatment option for adults.
  • IFN-γ: third-line treatment option.
  • Systemic steroids: not recommended.
  • Intravenous immunoglobulin: not recommended.
  • Montelukast (Singulair): not recommended.
  • Traditional Chinese herbal medicine (TCHM): not recommended.
  • [glossary slug=’mycobacterium-vaccae’ /]: not recommended.
  • Thympopentin-5 (an immunostimulant): not recommended.

What was not included:

What needs to be stated:

  • All of these medications can have significant side effects.
  • It is important to maximize topical treatments, including moisturizers and medications.
  • It is important to identify and minimize exposure to triggers, including foods and contact allergens.

 

* Roekevisch E, Spuls PI, Kuester D, Limpens J. Efficacy and safety of systemic treatments for moderate-to-severe atopic dermatitis: A systematic review. Journal of Allergy and Clinical Immunology 2014; 133(2) 429-438.

Probiotics for the prevention and treatment of allergies

 Probiotics are defined as live microorganisms which when administered in adequate amounts confer a health benefit (FAO/WHO 2002). The potential benefits include inhibition of pathogens, improved integrity of the gastrointestinal (GI) barrier and enhanced immune responses. These effects may be useful for the prevention and treatment of multiple allergic conditions.

Rationale:

– Allergies occur more in developed nations. The hygiene hypothesis states that a highly sanitized environment provides insufficient bacterial stimulation at a young age. Without proper ‘training’ the immune system is unable to distinguish harmful bacteria from healthy foods (tolerance).

– As we get older, the GI associated immune system continues to play an important role. Unfortunately, the composition of gut microbiota can be altered by diet, stress, aging, antibiotics or infection.

– The composition and diversity of intestinal microbiota varies in allergic versus non-allergic children.

– Children born via vaginal delivery are less likely to have allergies than those children born via c-section. Exposure to beneficial bacteria in the maternal vaginal tract helps to colonize the child. Also, this benefit may occur in those children who are  breast fed.

Evidence:

– The effectiveness of probiotics for the prevention and treatment of allergies is controversial. There are a large number of published studies with a wide range of results. Several studies show a great benefit and several studies show no benefit at all.

– The variable results are likely the result of variable protocols. The strain of bacteria, the amount of bacteria and the age of the patient are important factors in determining outcome. It is likely that different strains produce different immunologic effects leading to different outcomes. One probiotic may help asthma and another may help eczema. Examples of beneficial probiotics include, Lactobacillus rhamnosus HN001 and Bifidobacterium longum BB536.

– Eczema (atopic dermatitis). Probiotics have shown value for preventing eczema when given to expecting mothers. Probiotics have shown value for treating eczema when given to young children.

– Allergic rhinitis (sneezing). Several studies from Japan have shown decreased allergy symptoms for patients with tree pollen allergy.

– Food allergy. Infant formulas supplemented with probiotics may improve the symptoms of milk allergic colitis. Unfortunately, supplementation did not accelerate cow’s milk tolerance in those infants with milk allergy.

Conclusion:

Probiotics may be a useful adjunct in the fight against allergic disease. They provide a natural way to stimulate the immune system. Most importantly, proper timing may prevent future allergies. Further research is needed to determine which strains are useful and when they should be taken.

FDA committee supports approval of two new sublingual allergy tablets

tabletsLast week, the FDA Allergenic Products Advisory Committee unanimously supported approval for two new sublingual allergy tablets (Oralair and Grastek).  Allergy tablets are an alternative to conventional allergy shots. Both tablets are indicated for the treatment of grass pollen allergy. Oralair is made by a French pharmaceutical company Stallergenes and contains 5 different grasses: Sweet Vernal, Orchard, Perennial Rye, Timothy, and Kentucky Blue Grass. Grastek (aka Grazax in Europe) is made by ALK-Abello and Merck and contains only Timothy Grass.  Although both tablets are available in Europe, FDA approval may not occur for a year or more.

For more than a century, physicians have been using the process of desensitization to treat environmental allergies. Introducing small amounts of allergen (i.e. dust mites, pollens) over and over again, helps to re-educate the immune system. Using current dosing regimens, the results are impressive. Large analyses show a decrease in allergy and asthma symptoms of ~ 75%. Other benefits include a decreased need for medications (60%) and decreased risk of developing new allergies or asthma. Unfortunately, these results require commitment and frequent office visits.

Which is better, allergy tablets or shots? 

1. Effectiveness. There have been few good studies comparing allergy tablets (or drops) with shots. Looking at placebo controlled trials (comparing treatment with a ‘fake’ injection or tablet), allergy shots appear to provide higher levels of relief.

Winner: shots.

2. Convenience. Each and every allergy shot must be given in the allergist’s office.  Although the first dose is given at the allergist’s office, allergy tablets are continued at home.

Winner: tablets.

3. Flexibility.  Those tablets currently available (in Europe) contain only single allergens, such as for grass. Other tablets in development include ragweed or dust mites. Allergy shots are customized by allergists to contain multiple allergens, such as for trees, grasses, weeds, dust mites, animal danders and/or molds.

Winner: shots.

4. Compliance. Without completing a recommended course of allergy tablets or shots, patients will not get their optimal result. Unfortunately, neither treatment route has demonstrated a high completion rate. A recent study from the Netherlands  found that only 7% of those getting allergy tablets (or drops) completed the recommended three years of treatment. Surprisingly, that was even worse than the 23% of patients getting allergy shots. One possible reason, allergy shots may be spread out to once monthly versus daily use of allergy tablets.

Winner: neither.

5. Cost. Producing a high quality allergy tablet (or drop) requires significantly higher amounts of material than allergy shots. However, there are less associated costs, i.e. office visits and injections. Unfortunately, an accurate comparison is not possible at this time, until allergy tablets are approved by the FDA, there is no insurance coverage.

Winner: unknown.

6. Safety. Both tablets and shots are well tolerated. Both have the potential to cause local reactions, either an itchy mouth or an itchy harm. Both have the potential to cause systemic (more severe) reactions. Although the risk is low, it is definitely higher with shots (compared to tablets).

Winners: tablets.

6. Conclusion. The best allergy treatment is one that works quickly and lasts forever. Allergy tablets, drops and shots will continue to get better. For example, four doses of an investigational cat vaccine, given over 12 weeks, had a significant improvement in symptoms two years later. Stay tuned.

 

Food additives, an unlikely cause of chronic hives

spicesIf you suffer from chronic hives (urticaria) then you are desperate to find a cause. The one allergy that will fix your problem. Often foods, food additives or food preservatives are suspected. When you break out every day and eat multiple times in a day then there is bound to be some overlap. A few months ago, I looked at the evidence for diet changes as a treatment of chronic urticaria (link). There were only a small number of studies with little evidence for or against the role of food allergy in causing hives. A new study attempts to provide a more definitive answer.

The study, from Scripps Clinic in San Diego, California was designed to overcome two main obstacles. The first obstacle is bias. If a patient believes that a food is causing their hives this may result in higher stress, anxiety and more hives. A blinded study is needed to prevent bias. In the final arm of their study, neither patients nor investigators were aware if they were ingesting a food additive or a placebo (sugar pill). The second obstacle is the medication used for treatment. Symptoms are controlled with anti-histamines, if these medications are stopped for the study then the hives will naturally recur. This could result in a false positive. On the other hand, if the patient is on ‘too much’ anti-histamine then a reaction may be masked (a false negative). The author’s solution was to maintain patients on a minimum effective dose of medication.

After completion (ten years), one hundred patients had been challenged with 11 food additives, including:

  • FD&C Yellow 5
  • FD&C Yellow 6
  • Potassium metabisulfite
  • MSG 2500
  • Aspartame
  • Sodium benzoate
  • Methyl paraben
  • Butylated hydroxyanisole
  • Butylated hydroxytoluene
  • Sodium nitrate
  • Sodium nitrite

Although 43 patients reported a history of reaction to food or drug additive prior to the study, NO patients reacted to a double-blind challenge. The conclusion, sensitivity to food additives appears to be rare in patients with CIU, and avoidance is NOT recommended. One study is not proof, but this new information does makes food additives as a singular cause of chronic hives fairly unlikely. We must continue the search for the environmental, infectious and immunologic factors resulting in this burdensome disease.

References:

Rajan JP, Simon RA, Bosso JV. Prevalence of sensitivity to food and drug additives in patients with chronic idiopathic urticaria. J Allergy Clin Immunol Pract. http://dx.doi.org/10.1016/j.jaip.2013.10.002.

Warning: May Contain Peanuts

labelCurrent treatment options for food allergy are limited. Chinese herbal therapy may prevent reactions. Oral desensitization may one day provide a more permanent cure. Unfortunately, neither treatment is available today. Instead, patients and parents are instructed to avoid a food (or group of foods) without error.

When eating out, you must rely on the kitchen staff. When eating at home, you must rely on the ingredient list provided by the manufacturer. These food labels may be inaccurate or difficult to interpret.

Reading a label is an acquired skill. In order to be successful, parents need to know the benefits and limitations of current labeling laws. Most important is the Food Allergen Labeling and Consumer Protection ACT (FALCPA); passed in 2004 and in effect since 2006. This law requires labels to plainly state, in clear english, if they contain a major food allergen. The major food allergens are milk, egg, fish, crustacean shellfish, peanut, tree nuts, wheat and soy). These ingredients must be listed if they are present in any amount, even in colors, flavors or spice blends. Additionally, the manufacturer must list the specific nut and/or seafood that is used. The food name can be found in one of two places;

1. Within the ingredient list; i.e. “natural flavoring (egg)”.

2. An adjacent “contains” statement; i.e. “Contains egg.” These are usually in bold type.

Passing this law was a step in the right direction. Unfortunately, there remain limitations;

• Only 8 foods groups are required. If you are allergic something else (i.e. sesame seed), it may not be included in the “contains” statement. If you are sensitive to something else (i.e. gluten or preservatives), it will not be included. You must read the full ingredient list.

• Alcoholic beverages, meat, poultry, and certain egg products are not regulated.

• Advisory labels for possible cross contamination are voluntary and inconsistent. Examples include, “May contain traces of peanut,” “Processed on equipment that also processes peanuts,” or “Made in a facility that processes peanuts.”

FALCPA requirements do not apply to potential or unintentional presence of major food allergens in foods resulting from ‘cross-contact’ situations during manufacturing, e.g. because of shared equipment or processing lines. It is left to the discretion of the company if they would like to include a warning statement. The wording of such statements is also left to the company. There are no parameters. This lack of consistency lowers the value of all statements. Their high prevalence and ambiguity leads consumers to doubt their legitimacy. In the end, warning statements are often ignored.

The warning statement is only valuable if can convey the risk of contamination and help parents to make informed decisions. Useful information would include, the probability that the product contains peanut and the amount of peanut that may be present. Several studies have analyzed foods in order to answer these questions. A study from Ireland, looking at 38 food products with a nut statement, found detectable peanut in 5% of foods. The amount of nut protein varied from 0.14 to 0.52 mg per serving (or less than 1/100 of a peanut).  A more recent US study found that 8.6% of foods with a peanut advisory contained a detectable level of peanut protein. Nutrition bars contained the highest levels. Other high risk foods include chocolate candies, cookies and baking mixes.

The problem is not limited to peanuts and tree nuts. In a 2010 study of milk, egg, and peanut; the highest level of contamination was for milk (10.2%). Overall 5.3% of foods with an advisory label were contaminated. The levels of milk found were within the range that may cause a reaction. On the other hand, peanut levels were low. It was estimated that the level of peanut contamination would cause a reaction in only 5% of peanut allergic children, making the overall risk of reaction less than 1%.

The amount of protein that may cause a reaction (threshold) varies dramatically in different children. This makes label standards difficult. The Australian Allergen Bureau have been using investigation and statistics to overcome this obstacle. A Voluntary Incidental Trace Allergen Labeling (VITAL) program was developed to make a single simple standardized precautionary statement available to assist food producers in presenting allergen advice consistently for allergic consumers. VITAL not only assists food producers in assessing the potential impact of allergen cross contact in each of their products but also specifies a particular precautionary allergen statement to be used according to the level of cross contact identified. The initial goal was to label foods with peanut levels higher than 1.5 mg, the amount likely to cause a reaction in 5% of peanut allergic children. With VITAL 2.0, the level drops to 0.2 mg, only 1% of peanut allergic children will react at this level. Additionally, VITAL 2.0 provides manufactures with an action grid containing 24 total foods.

Recommendations that are not specific are not helpful. At this point, the safest course is to avoid any food that declares the major allergen. Parents must read labels ALL of the time. Ingredients can change. In the end, if you are unsure whether or not a product could be contaminated, you should call the manufacturer to ask about their ingredients and manufacturing practices.

Dust Mite Avoidance

broomOne in four Americans are sensitive to dust mites. If we include other components of house dust (pollens, animal danders, cockroaches and molds), the number is even higher.

Dust mites are arachnids, like spiders and ticks. They thrive in warm, humid climates; temperatures above 70 degrees Fahrenheit and humidity over 70%. Mites live off water in the air and ingest particles of human skin and animal dander. This is why the concentrations are so high in your mattress and bedding. However, dust mites are not bed bugs, they do not bite nor carry disease. Mites are only harmful to those people who are allergic. Dust mite allergy can result in several allergic conditions:

1. Allergic rhinitis: runny nose, congestion, sneezing and itching.

2. Asthma: cough, wheezing, shortness of breath.

3. Atopic dermatitis: eczema, itching.

People who are allergic to dust mites react to proteins within the bodies and feces of the mites. These particles are found mostly in pillow, mattresses, carpeting and upholstered furniture. They float in the air when anyone vacuums, walks on a carpet or disturbs bedding, but settle out of the air soon after the disturbance is over.

Research has confirmed that targeted avoidance (environmental control aimed at relevant triggers) can be as effective as medications in reducing symptoms. Here are some tips:

• Focus on reducing dust mite levels in the bedroom. Keep indoor humidity below 50%. This may require a dehumidifier. Do not use vaporizers or humidifiers. Use ventilation fans in bathrooms and kitchen. Use a vacuum with a HEPA filter. If you are allergic, wear a N95 filter mask while dusting, sweeping or vacuuming. Even better, find someone else to clean when you are not at home.

◦ Encase mattresses and pillow with ‘mite-proof’ covers.

◦ Wash all bed linens weekly using hot water ( > 130°).

◦ Remove wall-to-wall carpets.

◦ Remove plants, soft toys, cushions and upholstered furniture.

◦ Treat stuffed animals with fire and ice: Dust mites die at freezing temperatures. Put pillows and children’s stuffed animals in plastic bags and put them in the freezer for 24 hours. Alternatively, put toys in a fabric bag and place them in the dryer for 10 minutes. Remember to take off anything that could melt.

• Acaracidal sprays (i.e. tannic acid) can temporarily reduce mite levels in airborne, furniture and carpet dust. Application of liquid nitrogen to the mattress and carpets is slightly more effective and much more dangerous.

• Install a high efficiency media filter with a MERV rating of 11 or 12 in the furnace and air-conditioning unit. Change the filter at least every three months (with the change of the seasons).

• Portable HEPA filter air-cleaners are less effective at reducing dust mite levels. This intervention may be worthwhile for pet allergy (esp. cats).

There are more than 30 trials demonstrating the effectiveness of bed encasings for asthma. Financially, the one time cost is significantly less than a monthly copay. Unfortunately, the clinical benefit of covers alone was small. A complete program, including acaricides and extensive bedroom based environmental control is necessary. Benefits include decreased allergy and asthma symptoms, less medications and more savings.

Discovery Channel presents “An Emerging Epidemic: Food Allergies in America.”

FARE

FARE (Food Allergy Research & Eductation) has teamed up with The Discovery Channel to produce a new documentary about food allergies called “An Emerging Epidemic: Food Allergies in America.” The hour-long documentary, narrated by Steve Carell, explores what it is like to live with life-threatening food allergies, how families and individuals managing food allergies are working to raise awareness in their communities, and the vital research underway to find effective treatments and a cure.

Watch the full documentary online>

The documentary debuted on Saturday, September 7 and will air again on Saturday, September 21 at 8 a.m. ET/PT. The documentary will also be available for viewing online at www.discoverychannelpatienteducation.com and available for download on iTunes.

Egg Allergy & 2013-14 Influenza Vaccination

flukidThe CDC recently published vaccine recommendations for the 2013-4 influenza season (http://www.cdc.gov/flu/about/season/index.htm). Special attention is given to those patients with a history of egg allergy.

Influenza vaccine is grown in embryonated chicken eggs and contains residual amounts of ovalbumin, a major egg allergen. For patients with egg allergy, even small amounts of this protein can trigger an allergic reaction. This risk must be considered before vaccination . On the other hand, Influenza infection poses a significant risk itself. There are approximately 300,000 hospitalizations annually, including more than 20,000 in children younger than 5. Children with asthma are most vulnerable. This is concerning given the increased incidence of asthma in children with egg allergy.

Due to fear of allergic reaction, flu shots were previously withheld from all children with egg allergy. In order to assess risk, allergists began skin testing children with the influenza vaccination.  In 1977 physicians began immunizing those egg allergic children with a negative influenza skin test. About ten years later another group pushed further. This time, children with a positive skin test were successfully vaccinated using a multi-step protocol. The most recent studies (including those with H1N1 vaccine) have found the real risk of reaction to be exceptionally low. One recent study, vaccinated 143 children with documented severe egg allergy. No children had a significant allergic reaction take place. This data is prompting change. Beginning with the 2011-2012 season, the AAP, CDC/ACIP, and NIAID specifically recommend that patients with egg allergy receive the trivalent inactivated influenza vaccine (TIV) with some precautions.

Here is a quick summary of the most recent CDC recommendations:

1. Persons with a history of egg allergy who have experienced only hives after exposure to egg should receive influenza vaccine.

– Vaccine should be administered by a healthcare provider who is familiar with the potential manifestations of egg allergy; and

– Vaccine recipients should be observed for at least 30 minutes for signs of a reaction after administration of each vaccine dose .

2. Persons who report having had reactions to egg involving such symptoms as angioedema, respiratory distress, lightheadedness, or recurrent emesis; or who required epinephrine or another emergency medical intervention may receive egg-free vaccines, if aged 18 through 49 years and there are no other contraindications. If egg-free vaccines are not available or the the receipient is not within the indicated age range, such persons should be referred to a physician with expertise in the management of allergic conditions for further risk assessment before recipient of vaccine.

– All vaccines should be administered in settings in which personnel and equipment for rapid recognition and treatment of anaphylaxis are available.

3. For individuals who have no known history of exposure to egg, but who are suspected of being egg-allergic on the basis of previously performed allergy testing, consultation with a physician with expertise in the management of allergic conditions should be obtained prior to vaccination.

4. A previous severe allergic reaction to influenza vaccine, regardless of the component suspected to be responsible for the reaction, is a contraindication to future receipt of the vaccine.

Beyond the recommendations:

– Egg-free vaccines may be used for persons aged 18-49 years who have no other contraindications.  In 2012, the FDA approved Flucelvax, the first influenza vaccine produced without egg. A second vaccine, FluBlok, was approved in 2013.

– Skin testing is NO longer routinely necessary for patients with egg allergy. However, skin testing with the vaccine IS still appropriate when evaluating a patient with a history of reaction to the influenza vaccine itself, as opposed to a history of reaction to egg.

– Studies have shown ovalbumin (egg) content up to 1.2 ug/ml to be well tolerated. Most available vaccines have significantly less.

– Although intranasal vaccine (FluMist) contains one of the lowest absolute amounts of ovalbumin per dose, there are no data on its administration to patients with egg allergy. Thus, injectable vaccine only should be used for patients with egg allergy.

 

Eczema: To Bathe Or Not To Bathe

duckEczema is a common skin problem, affecting 10-20% of children. Dry, scaly patches and intense itching result in unhappy children and parents. Complications include bacterial infections, viral infections, bleeding and most importantly, sleep disturbance. Often allergic eczema (atopic dermatitis, AD) is the precursor to several allergic conditions; food allergy, asthma and allergic rhinitis.

Before getting wet let’s look at the causes of eczema. Genetic mutations and environmental factors combine to produce a skin-barrier defect. This ‘leaky’ skin barrier allows for excessive water loss. Additionally, local immune dysfunction, allergy and infection produce inflammation of the skin. Inflammation leads  to itching. Itching leads to scratching. Scratching leads to further inflammation. Treatment must restore health to the skin and break the itch-scratch-cycle.

There are a staggering number of treatment choices; oils, lotions, creams, soaps and ointments. Some are natural and some contain potent steroids. An effective treatment regimen should include a combination of medicines, specific for the individual patient. Rehydrating the skin is essential for healing the skin and preventing recurrence. Doctors advise frequent moisturizer use and bathing on a regular schedule.  Recommendations range from bathing twice daily to twice weekly. The frequency is likely based on physician training and experience.  There is little consensus and even less evidence which is best.

It is commonly accepted that bathing dries out the skin. Water not only washes away dirt but also natural oils. Use of soap and harsh detergents, such as sodium lauryl sufate (SLS), has been shown to remove protective skin lipids and natural moisturizing factors. Bar soaps are often highly alkaline and can result in further drying. They may have chemical additives (i.e. perfumes) that can act as irritants or allergens causing inflammation. Hot and very hot water contribute to inflammation as well. The problems don’t end when the bath is over. Aggressive drying creates friction and skin damage.

On the other hand, bathing has important benefits. Soaking in water may help to rehydrate skin cells. Cleaning bacteria from the skin reduces the risk of infection. The intermittent addition of bleach is effective in lowering the amount of bacteria living on the skin.

My conclusion, bathing can dry out the skin UNLESS done properly. Here are some tips for effective bathing and hydration:

• Keep water at a lukewarm temperature.

• The bath should last approximately 15-20 minutes.

• Avoid harsh soaps, bubble bath and hand washes. Instead use emollient washing products.

• Be gentle. Try not to rub your body too strongly with your towel.

• Apply moisturizer to slightly damp skin within three minutes of getting out.

• Intermittent use of antiseptic bath oils and dilute bleach can reduce flares.

• Other additives may be helpful, for example magnesium salts and natural colloidal oatmeal.

• Use LOTS of moisturizer following the bath and throughout the day. Emollients (moisturizers) and steroids should be applied in a 10:1 ratio.

Application should be separated by 30 minutes, 1 hour for tacrolimus. Remember not to insert hands or fingers directly into emollients, in order to avoid microbial contamination of the contents.

Can Diet Cure Chronic Hives?

Food dish

Food dishFat, Sick and Nearly Dead is a 2010 documentary which follows the journey of Australian Joe Cross (http://www.fatsickandnearlydead.com). Joe traveled the country during a 60 day juice fast. Nothing but liquid nutrition. His purpose; cure disease, reduce dependence on medications and lose weight. Joe has chronic hives (urticaria). He relies on multiple medications, including oral steroids, to control symptoms. Throughout the trip he undergoes a miraculous transformation. The number of pills and pounds continue to drop.

Should everyone expect these results? Probably not. A documentary film is not sound medical evidence. In this film, there is only one subject. There is no comparison group. Most importantly, hives frequently come and go on their own without reason.

A German study published in 2010 investigated diet manipulation for the treatment of chronic hives. Patients eliminated all processed foods, artificial substances, food additives, dyes, antibiotics, preservatives, phenols and natural foods rich in aromatic compounds such as tomatoes. What is most interesting, patients avoided the majority of Joe’s diet – NO fruit. The results were mixed; 34% benefited from the diet and 24% deteriorated while on the diet. Responders took on average 3 or more weeks to respond.

These doctors believe that artificial preservatives and dyes in modern processed foods (and aromatic compounds in some natural foods) act as pseudoallergens, substances causing allergy symptoms via non-allergic mechanisms. These foods trigger the release of histamine and subsequent hives without an allergic immune response. This suggests another possible link, those foods with high levels of histamine (http://chronichives.com/useful-information/histamine-restricted-diet).

An Italian group put patients on an oligo-antigenic and histamine-free diet for 21 days. They excluded foods with artificial coloring (esp. tartrazine), fermented foods, benzoates, Butylated hydroxyanisole (BHA) and butylated hydoxytoluene (BHT). Patients in this study had a significant improvement in symptoms. However, there were only 10 patients. Additionally, patients in a similar study out of Canada showed less substantial improvement.

Other foods under investigation for chronic urticaria include; MSG, parabens and aspartame. Alcohol and spices both can cause vasodilation (widening of the blood vessels) and hives in  patients with chronic urticaria. Unfortunately, hives continue to occur after elimination.

Overall, there is little scientific evidence to support elimination diets for the treatment of hives. We do not routinely advise patients to adopt a pseudoallergen free diet. However, there are patients who do not respond well to medications, who require multiple medications or are experiencing significant side effects. For this group, there is little risk in trying an elimination diet. Patients should be motivated. Patients should eliminate a large group of foods; although foods can be added one at a time (after hives have resolved), it is unlikely to help if they are removed one at a time. Most important, prolonged diet changes require the supervision of a doctor or nutritionist.