Boys underarm sweating odor may be related to fox odor, hyperhidrosis, poor hygiene habits and other reasons, need to be further differential diagnosis by a doctor. 1. Fox odor: genetically related, manifested as a special pungent odor in the armpits. It is especially noticeable in summer, after exercise, and during emotional stress. 2. Hyperhidrosis: associated with heredity, disease, medication and other factors, manifested as an abnormal increase in sweating, secondary bacterial or fungal infections can emit a foul odor, most commonly in the feet, armpits, perineal area. 3. Bad hygiene habits: If you don’t take a shower for a long time, underarm sweating may cause odor due to the growth of bacteria in the armpits. It is recommended that boys with smelly underarm sweating go to regular hospitals in time to clarify the cause, and if treatment is needed, standardized treatment should be carried out under the guidance of doctors to avoid delaying the condition.