The aim of this phase 1b study is to evaluate the safety and tolerability of the epicutaneous immunotherapy method in subjects allergic to peanut. The trial will randomize 110 participants. Four doses of peanut proteins, 20 mcg, 100 mcg, 250 mcg and 500 mcg will be repeatedly delivered on the skin by dose escalation in consecutive cohorts of 5 subjects, starting with the lowest dose. In each cohort of 5, 4 subjects will receive peanut proteins and one will receive placebo in a blinded manner. For each dose, the peanut proteins will be applied on the skin either every day or every other day. The total duration of the treatment for each subject is 2 weeks. Firstly, adult subjects (18 to 50 years) with a history of non-severe anaphylaxis to peanut (Grade ≤3) will enroll and safety information be reviewed. If there are no major concerns, adolescent cohorts (12 to 17 years) with history of non-severe anaphylaxis to peanut will then enroll and safety again be reviewed. If there are no concerns, then child cohorts (6 to 11 years) with history of non-severe anaphylaxis to peanut will finally enroll.