Hypoallergenic Diet in Dermatology

Katrina Canlas-Estrella, MD, FPDS

Diet is frequently associated in various skin disorders. One way in which diet affects skin disorders is the concept of food allergy. Food allergy is defined by the US National Institute of Allergy and Infectious Diseases as: “an adverse health effect arising from an immune response that occurs reproducibly on exposure to a given food”. Simply put, this occurs when there is a breakdown of the body’s tolerance to food ingested^1,2. Typical manifestations of a food allergy are skin reactions such as hives and itchiness, respiratory tract symptoms such as difficulty of breathing, and gastrointestinal tract symptoms such as vomiting and diarrhea. A severe and potentially fatal reaction called anaphylaxis, can also be experienced. While many advances have been made in understanding the mechanism, treatment and prevention of food allergy, the mainstay of treatment remains to be avoidance of the food allergen/s^1-5.

Allergenic foods comprising more than 85% of food allergy are egg, milk, peanut, tree nuts (walnut, cashew, pistachio), fish, shellfish, sesame seed, soy, and wheat. Several studies identify egg allergy as the most prevalent^4,5. In adults, allergies to certain fruits and vegetables are common³. Usually, many people outgrow their food allergies over time, such as hen egg and cow milk allergies. In contrast, peanut and tree nut allergies, along with shellfish allergy, are known to persist throughout life^1-3. In addition, nickel is also a very common allergen and this could be found in certain foods such as oatmeal, beans, peas, soybeans, shellfish, and chocolate^2,4,6.

A hypoallergenic diet is a diet composed of foods low in allergenicity. Specifically, it is free from soy, nuts, egg, dairy, corn, beef, gluten, shellfish, and citrus fruits. That said, patients on a strict hypoallergenic diet should be carefully monitored and properly managed so as to avoid nutritional deficiencies. In children, food allergies to milk, egg, soy, and wheat tend to disappear during late childhood and these specific foods may eventually be tolerated after 1 to 2 years. As mentioned, allergies to peanut, tree nuts, and shellfish typically persist and may be lifelong^1-4.

There are certain skin diseases that can benefit from a hypoallergenic diet. Several studies have shown that certain food allergens can lead to an exacerbation of a patient’s dermatitis. Specifically, food allergy has been shown to be present in 20 to 80 percent of patients with atopic dermatitis (AD). Thus, a hypoallergenic diet may be helpful in patients with AD. Other skin diseases that may benefit from a hypoallergenic diet are systemic contact dermatitis (SCD) and allergic contact dermatitis (ACD). Furthermore, acute vesicular hand dermatitis may benefit from a diet low in nickel-rich foods^2,4,6. 

In order to find out if one has a food allergy and identify the specific food/s one is allergic to, one may consult with an allergologist. A detailed history and thorough physical examination are important, then skin prick testing (SPT) or radioallergosorbent test (RAST) can be done to identify potential food allergens. Once potential allergens have been identified, one must always be vigilant in checking food labels and ingredients in order to prevent the unfortunate manifestations of food allergy. In the event of an allergic reaction, rescue medication should always be available^1-6.

References:

1. Renz, Harald, et al. “Food Allergy.” Nature Reviews, vol. 4, no. 17098, 4 Jan. 2018, pp. 1–20., doi:doi:10.1038/nrdp.2017.98. 
2. Katta, Rajani, and Megan Schlichte. “Diet and Dermatitis: Food Triggers.” The Journal of Clinical and Aesthetic Dermatology, vol. 7, no. 3, 2014, pp. 30–36. 
3. Chapman, Jean, et al., editors. “Food Allergy: A Practice Parameter.” Annals of Allergy, Asthma & Immunology, vol. 96, Mar. 2006, pp. 1–68. 
4. Dhar, Sandipan, and Sahana Srinivas. “Food Allergy in Atopic Dermatitis.” Indian J Dermatol, vol. 61, 2016, pp. 645–648. 
5. Waserman, Susan, and Wade Watson. “Food Allergy.” Allergy, Asthma & Clinical Immunology, vol. 7, no. Suppl 1, 2011, pp. 1–7. 

Kaimal, Sowmya, and Devinder Thappa. “Diet in Dermatology: Revisited.” Indian J Dermatol Venereol Leprol, vol. 76, no. 2, 2010, pp. 103–116.