The causes of increasingly serious spots on the back of the hand often include pigmentation diseases, age spots, flat warts and so on. 1. Hyperpigmentation diseases: if patients suffer from hyperpigmentation diseases such as pigmentation spots, the spots on the back of the hands will become more and more serious under the influence of factors such as prolonged exposure to sunlight or ultraviolet rays, prolonged mental stress, endocrine imbalance (oestrogen stimulates the secretion of melanin cells), etc. Such phenomenon is mostly related to the increase of melanin in the skin. 2. Age spots: this kind of disease is also called “seborrheic keratosis”, which is mainly manifested as round or ovoid papules or plaques on the skin of the patients, which are light brown in color and with clear boundaries; it is common in adults over 40 years old; the exact cause of the disease is still unclear, and it is currently believed that this disease is related to aging of the skin, genetic predisposition and other factors, and the enhancement of the above factors can cause more serious symptoms. The actual cause is not yet known, but it is believed to be related to factors such as skin aging and genetic susceptibility. 3. Flat warts: The spots on the back of the hands of the patient may also belong to flat warts; this disease is mainly caused by human papillomavirus infection, in the sun exposure, the immune system function of low and other factors, the spots on the back of the hands will have more and more serious situation. It is recommended that you go to a regular hospital, conduct a relevant examination, under the guidance of a professional doctor, to clarify the cause of the disease and to carry out targeted treatment.