The cause of lichen planus is still not known so it is difficult to understand how you can prevent it from occurring at all. But in case you have the condition already there are some things that you can do to prevent it from getting ugly. The patients with oral lichen planus are at a risk of developing oral cancer so it would be best to maintain a good oral hygiene and discontinue the use of alcohol and tobacco products. You should also avoid food that is spicy or tangy and the intake of caffeinated drinks like coffee and cola should also be minimized.
And to prevent the lichen planus of the skin from getting worse avoid scratching the areas at any cost. You can also get the areas dressed after applying the ointments if you are worried that you may end up scratching it. With certain precautions you can sure help yourself in getting over with the disease sooner.