Detailed answer

Hair and scalp lentigines, also known as sunspots or liver spots, are caused by excessive sun exposure and the overproduction of melanin in the skin. Allergies to skincare products, on the other hand, typically result in skin irritations and reactions such as redness, itching, or hives. These allergies do not directly cause lentigines. However, it is important to note that prolonged exposure to certain skincare products that contain allergenic ingredients can lead to skin damage and increase the risk of developing lentigines due to increased sensitivity to the sun. Therefore, it is crucial to protect the skin from sun exposure by using sunscreen and seeking shade to prevent the formation of lentigines and other skin-related concerns.