Clear blisters on the penis of toddlers may be caused by genital herpes, atopic dermatitis, scrotal eczema and so on. 1. Genital herpes: If parents do not clean the genital area of the toddler’s hygiene, it may lead to the invasion of pathogenic microorganisms, the appearance of transparent blisters on the penis, and also accompanied by pain, itching symptoms. 2. Allergic dermatitis: when young children come into contact with poor-quality toiletries, mosquito bites, dust mites, will prompt local allergic reactions, resulting in transparent blisters on the penis, accompanied by red spots, itching and other uncomfortable symptoms. 3. Scrotal eczema: If a young child lives in a humid environment or wears diapers for a long time, it may lead to scrotal eczema, and there are clear blisters on the penis, accompanied by itching. Parents should take their children to the hospital in time to find out the cause of the disease and early treatment to avoid delaying the condition.