What causes sudden appearance of many light brown spots on the back of the hand, and what should I do about it?
Dec 01, 2025
Source: Cainiu Health
Dr. Liu Wenmin
Introduction
In general, the sudden appearance of numerous light brown spots on the back of the hand may be caused by factors such as sunspots, friction or irritation, flat warts, lentigo simplex, seborrheic keratosis, etc. Improvement can be achieved through appropriate daily care, medication, surgical treatment, or other methods based on the specific condition. It is important to maintain proper sun protection and moisturization for the back of the hands and minimize external irritants in daily life.
Generally, the sudden appearance of numerous light brown spots on the back of the hand may be caused by sunspots, friction irritation, flat warts, lentigo simplex, seborrheic keratosis, and other conditions. Depending on the specific situation, improvements can be made through daily care, medication, or surgical treatment. A detailed analysis is as follows:
1. Sunspots: The back of the hand is often exposed to sunlight, and UV radiation stimulates melanocytes to produce excess pigment, forming light brown spots. Wear sunscreen gloves or apply SPF 30+ sunscreen when outdoors, avoid direct midday sun exposure, and use a gentle moisturizer each night to nourish the skin.
2. Friction irritation: Frequent contact with hard objects or repeated rubbing can thicken the stratum corneum and lead to localized hyperpigmentation. Reduce friction on the back of the hand, wear cotton gloves during household chores, and use non-irritating hand care products to maintain soft skin.
3. Flat warts: Caused by human papillomavirus (HPV) infection, which triggers abnormal epidermal cell proliferation, appearing as light brown flat papules. Topical treatments such as tretinoin cream, imiquimod cream, or fluorouracil ointment may be used under medical guidance. Laser ablation is also an option.
4. Lentigo simplex: Localized clustering and proliferation of melanocytes, presenting as isolated light brown spots. Under medical supervision, topical agents like hydroquinone cream, azelaic acid cream, or tretinoin cream may help fade the spots. Cryotherapy may be considered if necessary.
5. Seborrheic keratosis: Resulting from aging and overgrowth of keratinocytes, commonly occurring with age,表现为light brown plaques. Topical treatments such as tazarotene gel, adapalene gel, or vitamin A acid cream may be used under a doctor's guidance. In severe cases, curettage for seborrheic keratosis may be performed.
Daily protection including sun protection and moisturizing for the back of the hand should be maintained to reduce external irritation. Avoid scratching the spots randomly to prevent infection and spreading. Regularly monitor any changes; seek medical evaluation promptly if there is a sudden increase in number or changes in appearance.
