What to consider with pediatric allergies

Allergies can be a tricky problem to tackle in general pediatrics. The presentation and source of allergies can vary widely, with children experiencing everything from running noses to hives, caused by triggers like pets, food, and environmental factors.

Narrowing a focus for general practice, and when to involve a specialist can be difficult. Margaret T. Redmond, MD, a pediatric allergist at Nationwide Children’s Hospital in Columbus, Ohio, offers some insight to help manage allergies in general pediatric practice, and advice on when to seek help.

Q: What are the most common allergy issues a pediatrician should expect to encounter in general practice?

A: In terms of prevalence, allergic rhinitis is likely the most common allergic condition that a pediatrician will manage, estimated to affect up to 30% of children. Asthma and eczema are also quite common in childhood. Both asthma and eczema tend to be most severe in the first few years of life. A minority of children with asthma and eczema continue to have significant symptoms into school age. Although food allergy is estimated to effect only 6 to 8% of children, food allergic reactions can be severe and are a source of anxiety for parents.

Q: What assessments are recommended in general pediatric practice when it comes to identifying and diagnosing allergies in children?

A: Serum immunoglobulin E (IgE) testing for common environmental and food allergens is available in commercial labs and is a tool available to primary care pediatricians. Serum IgE testing and skin prick testing evaluate for the presence of specific IgE to a specific protein allergen. It is critical to understand that this testing modality is a risk prediction tool with an excellent negative predictive value, but not proof of diagnosis. The higher the specific IgE level, the more likely a patient is to have a reaction, but this does not predict the severity of the reaction. The gold standard test for allergy is challenge. The false positive rate in food IgE testing is 30%. If a child is tolerating a food without reaction and has the food removed from the diet because of a positive IgE level, the child can then lose their ability to tolerate the food without reaction. For this reason, we recommend focused testing when a history is suggestive of possible IgE mediated reaction and do not recommend panel testing for foods.

There are many other testing modalities that are marketed to patients including immunoglobulin G testing and cytotoxic testing. These testing modalities have not been shown to be effective in diagnosing allergy or intolerance.

Q: What advice should pediatricians share with parents/guardians of patients who have been diagnosed with allergies? What are some interventions they should be trained to perform?

A: Chronic rhinitis in children can be either allergic or non-allergic. Both can present with nasal congestion, rhinorrhea, and physical findings of infraorbital edema (“shiners”) and transverse nasal crease. Children with allergic rhinitis are more likely to have associated itch and ocular symptoms. In young children, adenoid hypertrophy is a common trigger of non-allergic rhinitis. It is very reasonable to attempt therapy with an oral second generation antihistamine. I would recommend not using a first generation antihistamine due to increased side effect profile. If the patient does not improve with oral antihistamines and is aged younger than 2 years, I would consider evaluation by an otolaryngologist before considering allergy referral. If the patient is aged older than 2 years, a trial of intranasal corticosteroid spray can be attempted.

Infants with moderate to severe eczema are at risk for developing food allergies, but food is very rarely the cause of eczema. I would encourage referral of infants with moderate to severe eczema to allergy to be evaluated for risk of peanut allergy with a goal of early introduction of peanut into the diet. However, current evidence does not recommend testing prior to introduction of peanut in all children or testing multiple foods in infants with eczema. Early introduction of allergenic foods (cow’s milk dairy, egg, peanut, tree nut, finned fish, shellfish, wheat, and soy) and maintaining the foods in the diet on a regular basis is recommended to help prevent development of food allergy in at-risk children. I would encourage that feedings not be medicalized and parents be encouraged to feed food as opposed to specialty products.

Most young children who wheeze only with upper respiratory illness do not have environmental allergies contributing to their asthma symptoms. Children who have an allergic component to their asthma often have identifiable environmental triggers to their symptoms, particularly if they are seasonal or pet dander.

Q: What’s the best advice you can give to pediatricians in terms of managing patients with allergies?

A: Not all hives are allergic. In fact, the most common identified trigger of acute hives in children is infection. If the hives are being caused by an allergy, the parent should be able to identify an exposure that occurred within the preceding hour or so prior to reaction. If the child ate the same foods within the last 1-2 weeks without reaction, it is unlikely that tolerance would have been lost so quickly and therefore food allergy is much less likely. If your patient has hives without a clear historical trigger, it is reasonable to treat symptomatically with a second-generation antihistamine daily. In some patients, the hives can be so significant that twice-daily dosing of second generation antihistamines are needed to control hives. In a minority of patients, the immune process triggering activation of the mast cells and hives can persist for months requiring continued symptomatic management. These patients can always be referred to an allergist. However, if the child and parent understand that the hives are likely not being caused by an external exposure, this can significantly reduce the stress that the hives cause.

Children with a history of delayed rash while taking an antibiotic without any associated fever, joint pain or swelling, blistering rash, mucosal lesions, or organ involvement are very likely to be able to tolerate that medication again in the future and would likely benefit from evaluation to resolve that medication from their allergy list. Equally, children with a history of anaphylaxis to penicillin that occurred greater than 5 years earlier have a 50% likelihood of having developed tolerance to penicillin and may also benefit from an allergy evaluation.