Why You Should Address Atopic Dermatitis (Eczema) in Infants
By Lil Mixins Research Staff
It is by now well understood that eczema and food allergy are strongly associated. The presence of atopic dermatitis (AD) in infants is considered a risk factor for sensitization to food, food allergy, as well as rhinitis and asthma. (Epidemiologic risks for food allergy Lack G, JACI 2008). In fact, the age of onset of AD, and the severity of the AD, are strongly correlated to the risk of food allergy. (P. E. Martin et al 2014)
As seen in the data above, patients who developed eczema at age 0-3 months which required prescription strength corticosteroids, had a 50% rate of food allergy, whereas infants who developed AD at age 10-12 months that did not require topical treatment had a 5% rate of food allergy.
AD skin lacks fillagrin, which creates a proper barrier from ingress of external particles (food dust, dander) and limit trans epidermal water loss.
New research in a mouse model done by Raif Geha, MD and Mauel Leyva-Castillo, PhD at Boston Children’s Hospital, showed for the first time that scratching the skin promotes allergic reactions to foods, including anaphylaxis. The study showed how injury to the skin from scratching could rev up mast cells. In the mouse model, the skin breaks created a chain reaction in the small intestine, activating the mast cells that spur allergic reactions.
Eczema and the NIAID Guidelines for Early Introduction
The text from the “Addendum guidelines for the prevention of peanut allergy in the United States” state that patients with “severe” as opposed to “mild-to-moderate” eczema should approach peanut introduction differently. Whereas infants with mild-to-moderate eczema can approach foods with almost no concern, infants with severe eczema may need to see a specialist, have skin prick / SIgE testing done, and may need to do an oral food challenge.
Severe eczema as it relates to food allergies is defined as “persistent or frequently recurring eczema, with typical morphology and distribution assessed as severe by a health care provider and requiring frequent need for prescription-strength topical corticosteroids, calcineurin inhibitors, or other anti-inflammatory agents despite appropriate use of emollients”
Oh, circular logic.... Severe eczema is eczema that a health care provider assesses as severe!
So how do you properly differentiate between mild, moderate, and severe eczema?
Getting a Proper Patient History
Many caregivers have difficulty communicating the extent and severity of symptoms with accuracy, especially because baby skin is sensitive and rashes easily. Furthermore, eczema and its symptoms may come and go causing more confusion.
The SCORAD (SCORing Atopic Dermatitis) tool can be a good reference point for your evaluation. Though many do not use it in day-to-day practice, it has been extensively studied. It can also help an overwhelmed parent know what to pay attention to.
SCORAD takes into consideration the total surface area of the body that is affected, the severity of the visible symptoms, and the subjective symptoms (itchiness, inability to sleep).
Pucci et al (Allergy 2005) report that “the distribution of AD is largely age dependent. In the first 2 years of life (infantile phase), the primary clinical lesions of AD are mainly erythema, edema, oozing and crusting; the areas affected are the head (cheeks and chin are particularly involved), the scalp and extensor areas of the limbs.” “Moreover, there was a strong positive correlation between the SCORAD Index results and the extent, intensity and subjective symptoms.” Pucci et al suggest that while crude, these findings imply a single parameter, such as redness, is a pretty good stand-in for overall severity.
Your patients can describe what skin issues they are noticing. Ideally, they will be taking photos when possible.
In particular, they can answer the following questions:
What areas of the body are affected?
- Diaper area
- Inside the elbows
- Behind the knees
Do they see:
- Oozing and crusting of the skin?
- Severe redness that won’t respond to emollients?
Does the baby:
- Seem to loose sleep from itching?
What Qualifies as Severe?
In an infant patient, the extent of eczema is usually limited to the face, diaper area, and flexion points. More widespread eczema is more severe. Severe redness that does not respond to emollients or occasional use of over the counter hydrocortisone is likely severe. Lastly oozing or crusting is uncommon in infant patients that are not capable of scratching.
It’s Severe Eczema. Now what?
For infants with severe eczema, NIAID guidelines recommend that evaluation with peanut-specific IgE (peanut sIgE) measurement should be strongly considered before introduction of peanut to determine if peanut should be introduced. Panel testing for all allergens is not recommended, due to high false-positive rates.
Because a peanut sIgE level of less than 0.35 kUA/L has a strong negative predictive value for peanut allergy, sIgE testing can both speed introduction of peanut and limit unnecessary referral to a specialist. However, an infant with a peanut sIgE level of 0.35 kUA/L or greater should be referred to a specialist for an oral food challenge. Specialists suggest calling the office rather than simply referring a patient to ensure that an infant is seen in a timely manner.
Infants with severe eczema who have a sIgE level <0.35 or who have passed an oral food challenge should begin introduction of age-appropriate peanut as early as 4 months of age to reduce the risk of peanut allergy. Other solid foods should be introduced before peanut to show that the infant is developmentally ready.
Given what we know about the association between eczema severity and food allergy, as well as the causal pathway between broken skin and sensitization to foods, getting eczema under control is of utmost importance.
Together, early introduction and proper treatment of eczema can have the greatest impact on reducing rates of food allergy going forward.
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