White patches on the skin could be because of a number of conditions and depend on the nature and visual appearance of the same. If these look like small dots on the legs without a flaky scaling appearance then you probably have a vitamin B12 deficiency. If there are larger swathes, then there is a chance that you are experiencing the start of a case of vitiligo. The final but remotest possibility is that you are experiencing tinea versicolor but this is unlikely on the legs as the skin in the legs doesn’t secrete enough secretions to harbor large colonies of fungi necessary to cause the condition.
Vitamin B12 is an essential vitamin. This means that its deficiency causes debilitating conditions and widespread malaise throughout the body. The vitamin is crucial catalyst for the cell division process and its deficiency will cause deficient cellular growth. The reason why the white spots occur and are a symptom is because skin pigment, melanin, is created by cells in the body called melanocytes. When there is a vitamin B12 deficiency in the body, the melanocytes cannot perform the function of creating melanin. Additionally, the melanocytes might just die away and not be replenished. This causes a depigmented spot on the skin, which will go away as soon as you tank up on the vitamin. Unfortunately, this is one of the worst absorbed vitamins in humans. Humans cannot acquire this vitamin from plant sources and even if animal sources are used, the absorptive rate is too low; therefore, the only way out is to take oral supplements or pills. Buy these from your local pharmacy and swallow one pill every evening or before you go to bed. Over the course of the next few weeks, you will start to notice a difference.
The other possibility for the spotting is vitiligo. Here, the melanocytes are killed off by the body’s own immune system erroneously making it an autoimmune disorder. Increase your intake of a substance called psoralen from parsley and celery. Psoralen will improve UV radiation absorption causing the body to create more melanocytes in response to the exposure. Another treatment option is to increase black pepper intake. In both of these methods, you need to spend some time exposing just your leg to the sun for about an hour. You can also consider using a mixture made of mustard oil and turmeric. The turmeric for making the mixture needs to be soaked overnight in water. Once the mixture is ready, warm it up and apply it on the affected area.