The causes of spots on the back of the hand at the age of 30 include freckles, pigmented nevi, chloasma, pigmented dry dermatosis, etc. The treatments include medication, physical therapy and surgery. 1. Freckles: If it is freckles, there is no need for special treatment at this time, but if it has high cosmetic requirements, it can be treated by physical methods such as laser and freezing. 2. Pigmented nevus: if the spot on the back of hand is pigmented nevus, it usually does not need special treatment and can be treated by surgical excision if necessary. 3. Melasma: For patients with melasma, 2%~5% hydroquinone cream can be given at this time to lighten the plaque. 4. Pigmented dry dermatosis: at this time, you can give vitamin A, niacinamide and other drugs to treat. Finally, the phenomenon of 30-year-old spots on the back of the hand please seek medical attention, the above drugs must be used under the guidance of a physician.