I think the question is very nonspecific and requires more questioning to reach to a conclusion,but on Epping which I have picked up that its obviouse while you work or stand for a long time directs me towards Gravitaional Eczema
. I would have also asked you about any swelling in the legs or any Varicosities.
If you have such type of problem then you have to take certain measures along with some treatment. I would advise you not to stand for a long time,take regular walks and elevate your legs on a chair if sitting.
Keep the legs well moisturised with white petroleum jelly or Vaseline.
You can also apply potent to moderate topical steroids
to relieve the situation.But what would be best is to see a dermatologist
to have look and the proceed further as I cannot comment more without seeing it in a picture and with a brief history.
Thanks very much and all the best.