Pimple-like growths in the armpits may be folliculitis, eczema, sebaceous cysts, prickly heat, and so on. 1. Folliculitis: the distribution of hair follicles in the armpit is exuberant, and the secondary infection of hair follicles may lead to the protrusion, swelling, and pain of hair follicles, resulting in the growth of something similar to pimples in the armpit. 2. Eczema: Inflammatory skin reactions caused by internal and external stimuli may also cause acne-like underarms, and the acute stage will be accompanied by obvious oozing tendency. 3. Sebaceous cysts: sebaceous gland ducts are blocked, sebaceous gland secretions can not be discharged in a timely manner, the formation of cystic structures on the skin surface, resulting in underarm acne-like things. 4. prickly heat: high external temperature will cause excessive sweating of hair follicles, sweat discharge is not smooth may also cause prickly heat, resulting in armpit long acne-like things. There may be other reasons for acne-like underarm growth, and it is recommended that you go to the hospital in time for examination and treatment as prescribed by the doctor.