Small pimples on the genitals may be caused by glansitis, condyloma acuminatum, genital herpes, allergy, pearl rash and other causes. 1. Glansitis: manifested as redness and swelling of the glans, the surface can form a red rash or erythema, can also be accompanied by local itching and pain and other symptoms. The combination of clinical manifestations and physical examination can assist in the diagnosis. 2. Condyloma acuminatum: it can be manifested as scattered or clustered pink or white genital organisms, accompanied by itching, burning pain and other symptoms, can be clearly diagnosed through biopsy. 3. Genital herpes: also manifested as small pimples on the genitals, in the form of blisters, can also be accompanied by pain, combined with the clinical manifestations and signs can assist in the diagnosis. 4. Allergy: when the genitals due to contact with allergens are prone to allergic reactions, local itching, redness, swelling, pimples and other symptoms, combined with the medical history, clinical manifestations can assist in the diagnosis. 5. Pearl rash: mostly due to the long prepuce or chronic inflammatory stimulation and other reasons, can also be manifested as white or reddish pimples on the genitals, do not blend with each other, and no discomfort symptoms. When there are small pimples on the genitals may have other reasons, it is recommended to actively seek medical attention, under the guidance of a professional physician for diagnosis and treatment.