Experimental designs for inductions of atopic dermatitis and food allergy. (a) Five-week-old female BALB/c mice were divided into naïve (n = 7), sham (n = 12), PCB (n = 12), and dexamethasone (n = 8) groups. 25 mg/kg of PCB extract was orally administrated from day 0 to 61. For induction of atopic dermatitis, each 1% DNCB and 10 mg/mL of HDM extract was applied to each ear once a week from day 21 (total six times). (b) Six-week-old female BALB/c mice were divided into naïve (n = 5), sham (n = 9), PCB (n = 9), and dexamethasone (n = 5) groups. To induce food allergies, mice were immunized with 20 μg OVA and 2 mg Imject Alum by intraperitoneal (i.p.) injection on day 0. From day 17, mice were orally challenged with 50 mg OVA in saline every 3 days, for a total of six times. Next, 25 mg/kg PCB extract was administered orally daily from day 17 to 34.