Oral administration of β‐carotene or lycopene prevents atopic dermatitis‐like dermatitis in HR‐1 mice

Atopic dermatitis (AD) is a chronic relapsing eczematous skin disease. Certain populations of patients are resistant to standard therapies with topical steroids and/or calcineurin inhibitors, and require systemic medication, such as immunosuppressants. Recently, several reports have shed light on the anti‐allergic effects of carotenoids. Therefore, we investigated the effect of p.o. administration of β‐carotene or lycopene on AD‐like symptoms of HR‐1 hairless mice fed with a low zinc/magnesium diet. Mice were divided into four groups: (i) fed with a standard diet (Co group); (ii) low zinc/magnesium diet (HR group); (iii) low zinc/magnesium and β‐carotene diet (HR‐C group); and (iv) low zinc/magnesium and lycopene diet (HR‐L group). They were then fed these diets for 8 weeks. Severities of dermatitis were assessed by their appearance, and histopathological and hematological observations. Mice in the HR group developed AD‐like dermatitis both clinically and histologically. HR‐C and HR‐L group mice also developed xerosis and wrinkle‐like skin changes, but they were milder than those of HR group mice. Histological analysis revealed that epidermis thickening and inflammatory cell infiltration in the skin of the HR‐C and HR‐L groups were both statistically less than those of the HR group. The concentration of thymus and activation regulated chemokine in the skin of the HR‐L group and the concentration of CCL27 in the skin of the HR‐C group were significantly lower than those of the HR group, respectively. In conclusion, p.o. administration of β‐carotene or lycopene prevents AD‐like symptoms in association with a suppression of T‐helper 2 chemokines in a murine model. Ingestion of carotenoids may be beneficial for patients with AD.