I want to know what lichen planus rash is, and how you catch or not catch it?

Not contagious. While not everything is known about lichen planus is not thought to be contagious, even though it will sometimes clear up with use of an oral antibiotic or antifungal med. Classic appearance is flat-topped pinkish bumps with a lacy white pattern over the surface. These are commonly found on wrists and shins but many other sites can be affected, including lips, mouth, genitals, and even nails.