Journal Scan / Review · August 03, 2022 Food-Induced Skin and Mucosal Pruritus: Clinical Characteristics, Pathophysiology, and Recommendations Dermatitis

TAKE-HOME MESSAGE

• The authors review the pathophysiology, presentation, assessment, and management of food-induced skin pruritus. The common sources of food-induced skin pruritus include histamine-rich foods such as nuts, seafood, vegetables, wheat, dairy, soy, legumes, and spices. Immune-mediated pruritic food reactions include food allergy syndromes, immunologic urticaria, dermatitis herpetiformis, delayed food-triggered atopic dermatitis, and fixed food eruption. Non–immune-mediated pruritic food reactions include phytophotodermatitis and histamine intolerance.

• The key to the diagnosis of food-induced urticaria or pruritus is obtaining a thorough medical history and the potential triggers of food-induced urticaria can be further investigated using skin prick testing, oral food challenges, or elimination diets.

–  Katherine M. Stiff, MD

Written by

 

 

Matthew J. Zirwas MD

When I saw the title of this article I was terrified. I spend inordinate amounts of time convincing patients that their itch is not being caused by foods. Gil Yosipovitch is the itch expert in the world though, and I thought maybe I was wrong, and foods did cause itch, and I'd been missing it for years.

Thankfully, this is a review of entities in which foods cause a rash that is itchy, and most are things that the majority of dermatologists are already aware of:

1. IgE-mediated food allergy can present as anaphylaxis but is extremely rare as a cause of chronic spontaneous urticaria.
2. IgE-mediated food allergy can present as oral allergy syndrome — immediate itching and mild swelling of the mouth and throat upon eating relevant foods.
3. Histamine intolerance: Patients with a relative deficiency of the GI enzyme "diamine oxidase" who can get itching from foods that have high levels of histamine — mainly fermented foods, wine, and aged meats or cheeses. This is supposedly common, but I've only found diamine oxidase supplements helpful in 1 patient over 20 years of caring for itch and dermatitis patients.
4. Fixed food eruption: Same idea as a fixed drug eruption, but triggered by a food rather than a drug — may be the answer when you see what looks like a fixed drug, but there aren't any prescription or OTC meds. A food diary helps here.
5. Dermatitis herpetiformis: We're all familiar with this one already.
6. Food -triggered atopic dermatitis: Does happen in kids under age 6, very controversial if it ever happens in adults (I don't think it does).
7. Systemic contact dermatitis: Reactions to ingestion of foods high in nickel (legumes, oatmeal, peanut butter in particular) is a very well–documented entity that likely affects about 1% of the population and triggers nonspecific dermatitis and itch. It can be diagnosed via a positive nickel patch test followed by improvement while following a low-nickel diet. In my experience, this is one of the few situations in which  patch testing can lead to clearance of a widespread, nonspecific dermatitis. My favorite resource for a low-nickel diet can be found by googling this: Rebelytics Low Nickel Diet.

Abstract 

Itch occurs in various dermatologic and systemic conditions. Many patients report that certain foods instigate itch, although there is limited published information in dermatology on food-induced pruritus. In addition, itch severity is rarely mentioned. Food can induce pruritus through either ingestion or direct contact with skin or mucosal membranes. The most common type of itch provoked by food is acute urticaria, often through the classical immunoglobulin E (IgE)–mediated pathway. Other mechanisms include non-IgE–mediated, mixed (IgE-mediated and non-IgE–mediated), T-cell–mediated, and nonimmune reactions. For patients presenting with urticaria, generalized pruritus, oral pruritus, or dermatitis, a thorough history is warranted, and possible food associations should be considered and assessed. Although any food seems to have the potential to elicit an immune response, certain foods are especially immunogenic. Treatment includes avoidance of the trigger and symptom management. Careful consideration should be used as to avoid unnecessarily restrictive elimination diets.

Dermatitis

When Foods Cause Itch: Clinical Characteristics, Pathophysiology, and Recommendations for Food-Induced Skin and Mucosal Pruritus

Dermatitis 2022 Jun 29;[EPub Ahead of Print], A Vander Does, T Ju, G Yosipovitch 

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Benjamin Hidalgo-Matlock
Skin Care Physicians of Costa Rica

Clinica Victoria en San Pedro: 4000-1054
Momentum Escazu: 2101-9574

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