The recent COVID-19 pandemic provoked an outstanding increase of infection-control measures, with chlorhexidine becoming an extensively used antiseptic. Allergic contact dermatitis to chlorhexidine is considered as a rare event in children, is often difficult to identify, and its diagnosis is often misdiagnosed as other skin diseases. We aimed to explore the sensitization to chlorhexidine-containing antiseptics in infants and children to determine the origin of their sensitization and the role of the excipients in their dermatosis. We performed patch tests with chlorhexidine digluconate 0.5%, benzalkonium chloride 0.1%, benzyl alcohol 10%, 5% and 1% in ten children (1-16.5-year-old) with severe contact reactions to chlorhexidine-based antiseptics (Biseptine®) and cosmetics. We also performed patch tests with sodium benzoate 5% in four of the children. Results were measured according to criteria recommended by the International Contact Dermatitis Research Group. Patch test reactions revealed that most children were sensitized to at least two components of chlorhexidine-containing antiseptics (chlorhexidine, benzyl alcohol and/or benzalkonium chloride). To explore the origin of the sensitization, we searched for umbilical cord care with chlorhexidine- containing antiseptics and the use of cosmetics and drugs containing chlorhexidine and excipients of chlorhexidine-containing antiseptics. Most parents reported prior disinfection of umbilical cord with chlorhexidine-containing antiseptics, but this was not always the case. Allergic contact dermatitis to chlorhexidine, benzyl alcohol and benzalkonium chloride should be considered in infants and children with severe eczema and concomitant allergies. The regular use of cosmetics and drugs containing chlorhexidine, benzyl alcohol, benzalkonium chloride or sodium benzoate should be cautioned or avoided in children with severe eczema or pre-existing allergies. Early suspicion and allergology exploration of allergic contact dermatitis to chlorhexidine-containing antiseptics and their excipients is of paramount importance to help prevent severe allergic reactions to topical antiseptics and numerous cosmetics.