Drinking Cow’s Milk Does Not Cause Eczema

Eczema is a chronic inflammatory skin condition, characterized by dry skin that may have red, intensely itchy patches.¹ Atopic dermatitis is the most common form of this skin condition. According to the World Allergy Organization, eczema affects 15% to 20% of young people and 2% to 5% of adults worldwide, and approximately 50% of people with eczema have allergic sensitivity, with a specific immunoglobulin E (IgE) response to allergens.²

Causes of eczema

The exact causes of eczema remain unknown.¹ However, certain genetic, environmental, and immunological factors, or a combination of these factors, appear to be involved in this skin condition.^1-4 Environmental triggers that can prompt eczema flare-ups include certain soaps, fabrics and deodorants, carpet fibres, dust, microbes, extreme temperatures, psychological stress, and some foods or food allergens.^1,4

Although there is no known cure for eczema, various approaches are used to reduce its symptoms.  Among such strategies, the exclusion of certain foods or food allergens is used under the pretext that these foods worsen eczema symptoms; however, this link has not been clearly demonstrated.³ Moreover, an expert panel reported that multiple studies have found that 50% to 90% of people who consider themselves to be allergic to certain foods do not, in fact, have allergies.⁵

Cow’s milk exclusion

Excluding foods or allergens is not systematically recommended because there is a lack of good quality scientific evidence demonstrating a reduction in eczema symptoms.^1,4,6 Despite this, the exclusion of certain foods is still a common practice. In fact, there are risks associated with adopting an elimination diet, such as nutritional deficiency, effects on child growth and development, social isolation, anaphylaxis after the reintroduction of excluded foods, and suboptimal health.⁴ For children, a dairy-free diet may increase the risk of calcium, protein, and calorie deficiency.² Moreover, there seems to be little benefit for individuals with eczema symptoms who have not been diagnosed with allergies in eliminating cow’s milk from their diet.^3,6

A British study of participants with eczema found that 68% of children and 46% of adults excluded one or more foods from their diet, although only 66% reported having had an allergy test.⁷ The main reason cited by participants for excluding foods was food intolerance and allergy (83% of children and 60% of adults). Among these participants, 40% of children and 52% of adults excluded foods to reduce the severity and symptoms of eczema.⁷ In this study, the most commonly excluded food was cow’s milk, followed by eggs, peanuts, nuts, seafood, fish and wheat. Other foods may be excluded, for example citrus fruit and soy.¹

For people with eczema who have a proven food allergy, exclusion of the food allergen could potentially improve symptoms of moderate to severe eczema.⁴ However, studies are needed to confirm the benefits of excluding certain foods.^3,6
 

The link with food allergies

Food allergies do not cause eczema. However, in some cases, a food allergy can trigger an eczema flare-up, as can other environmental triggers.¹ Clinical studies have documented the prevalence of a food allergy in 20% to 80% of atopic dermatitis cases.⁸

The fact that a food allergy co-exists with eczema does not necessarily prove a cause-effect relationship, and food allergies are not always linked to eczema getting worse. A Canadian study conducted in a First Nations community in Labrador found elevated IgE levels in children with and without eczema, with mean values at least 10 times higher than other populations.⁹ However, their sensitivity to eggs, milk, or wheat was not different from that observed in other populations.

The relationship between eczema and food allergies is complex.^4,7 Although many children with eczema may also have allergies, the direct role of certain foods in the severity of the disease has not been clearly demonstrated.⁶ The Eczema Society of Canada does not recommend undertaking elimination diets, or withholding foods or entire food groups, for long periods of time without consulting a doctor or an allergist to confirm an allergy to the eliminated food.¹ If exclusion of a food or food group is warranted, consulting a registered dietitian to ensure an adequate nutritional intake is also recommended.