Harsh soap and excessive washing may be contributing to rising numbers of allergies and allergic diseases, say scientists.
Robin Callard and colleagues from Great Ormond Street hospital believe abrasive skin care products strip away a protective layer of skin, leading to eczema and other allergic diseases.
They say this theory beats the alternative "hygiene hypothesis" that blames reduced exposure to infectious diseases in childhood for a weakened immune system and increased allergic responses.
Callard explains: "Too much washing with strong soaps, using exfoliants and other such skin care products, and perhaps biological washing powders could be stripping away the skin's outer protective layer, resulting in allergic responses to allergens in susceptible individuals. "
His team have demonstrated that if the skin's outer layer is stripped away, allergens and other proteins can penetrate it and be taken up by cells in the epidermis.
Study author John Harper added: "From a clinical viewpoint, it is important to stress we think it is over zealous washing using harsh detergents and or abrasive skin products that can damage the skin, that are likely to be at fault, not normal washing or normal standards of cleanliness."