Panel Reviews Dietary Triggers, Best Practices for Management of Dermatologic Diseases

Dietary triggers may play a mediating role in the symptom burden of several dermatological conditions, but completely abstaining from certain foods could lead to an increased risk of developing anaphylaxis and overall worse health outcomes, noted panelists during a Saturday session at the 2022 American Academy of Dermatology (AAD) Annual Meeting.

When advising patients with atopic dermatitis (AD), whose disease is characterized by high morbidity, Peter A. Lio, MD, FAAD, assistant professor of Clinical Dermatology and Pediatrics at Northwestern University’s Feinberg School of Medicine and the director of the Northwestern University Eczema Care and Education Center, said that the subject of food and skin commonly comes up during appointments, which can garner passionate opinions potentially rooted in misinformation.

“Many families and patients come in convinced food is the reason for the skin problem….The truth is, though, that when we look at unselected patients, meaning people that don't have a known specific food allergy, the data really suggests that just excluding foods really doesn't help,” said Lio.

Lio highlighted that the perceived prevalence of food allergy and food intolerance is more than 10 times higher than the true definition of both measures, which causes a disconnect or overinflation of how food impacts AD burden.

Utilizing the gold standard of double blind placebo-controlled food tests, he said that measuring patients over a course of 2 to 3 weeks is advised to examine for potential dietary-related exacerberations in patients.

For those who present with allergic immunoglobulin E (IgE) immune reactions (urticaria, angioedema, anaphylaxis, oral allergy syndrome), serological testing is available to test and confirm certain food allergies. Moreover, presence of comorbidities such as celiac disease, which is more common in patients with AD, could also explain a gluten allergy.

But for other allergies that are unconfirmed, the likelihood of having a direct association with AD exacerbations is rare. Removing foods that may have been tolerable to begin with, such as gluten or peanuts, could consequently lead to the development of these allergies by altering the gut microbiome of patients.

“Part of the issue is that so much energy, time, and money is put into [restrictive diets] that I think it can actually damage the ability to treat AD properly,” said Lio.

Regarding foods known to cause allergic reactions in children and patients with AD, cow’s milk and hen’s eggs are considered the 2 most common causes.

A healthy diet overall, specifically paleo diets, as well as hemp seed oil, oolong tea, and probiotics in children were several dietary recommendations noted by Lio to have a potentially positive effect on symptom burden of AD.

“We keep saying what food is making your skin bad, but maybe what we should be saying is your skin is making you sensitive to all these foods—we've got to heal your skin, because now we understand that many of the patients probably are sensitizing either epicutaneously, in the broken skin barrier, or transcutaneously, it gets through the skin, and this is really, really important.”

The association between diet and psoriasis, another immune-mediated disease, was addressed by April W. Armstrong, MD, MPH, FAAD, professor of Dermatology and associate dean of Clinical Research, Keck School of Medicine at the University of Southern California, who spoke on the implications of gluten on disease severity, weight loss considerations, and whether any specific foods or nutrients may be helpful for patients.

Celiac disease is shown to appear twice as frequently in patients with psoriasis, who are also at increased risk of testing positive for antibodies indicating gluten sensitivity. For patients with psoriasis with confirmed celiac disease, engaging in a gluten-free diet is strongly recommended and has been indicated to ameliorate gastrointestinal symptoms and reduce disease severity.

Potential benefits have also been shown for those who test positive for markers of gluten sensitivity, with a 3-month trial of gluten-free diet recommended as an adjunctive intervention to standard medical therapies. Abstaining from gluten is not recommended for patients with psoriasis with unconfirmed allergies.

“You may have patients who will say: well, I think I should just indiscriminately get tested for gluten sensitivity. So, we actually have a negative recommendation from the National Psoriasis Foundation [NPF] stating to not recommend universal screening of serological markers for gluten sensitivity, because in patients without family history and GI symptoms, there can be a lot of false positives,” said Armstrong.

In evaluating other potential strategies to reduce disease burden, the NPF strongly recommends for overweight and obese patients with psoriasis to engage in a hypocaloric diet as an adjunct intervention along with all types of standard therapies.

Obesity has been associated with higher disease severity and reduced response to therapies, in which dietary interventons ranging from 4 to 6 months could lead to improved quality of life and reduced symptom burden of comorbid psoriatic arthritis (PsA), which develops in approximately one-third of patients with psoriasis.

“Weight reduction can have a mechanical effect on our joints," Armstrong said. "Even though we think of PsA as primarily an inflammatory joint disease, the inflammatary properties can get worse with mechanical stress.”

Low-quality evidence has suggested that adhering to a Mediterrean diet, specifically extra virgin olive oil consumption, and consuming omega-3 fatty acids could improve psoriasis severity, added Armstrong. Conversely, a Western diet may increase disease burden due to sucrose/sugar content, whereas a ketogenic diet has shown some promise but warrants increased investigation due to some conflicting findings.

Dietary triggers were also noted by other panelists for the dermatological conditions of contact dermatitis, acne, and inflammatory hair disorders:

• contact dermatitis severity triggers: metals in food (nickel, chromium, cobalt), balsam of Peru fragrance, and benzoic acid/benzoates
• acne severity triggers: Western diet, high glycemic index/glycemic load foods, dairy (particularly skim milk), whey protein supplements
• inflammatory hair disorder triggers: significantly low calorie intake, telogen effluvium, vitamin/mineral deficiency

“For those with real allergies, of course, we have to take that seriously,” concluded Lio. "But for those without allergies, it might be dangerous to just start avoiding foods. I just want to convey that I really care about the patient. We want them to get better. We don't want to waste time, energy, or cause harm. In the meantime, it's a good thing to recommend a healthy diet."