lichen planus

My husband is on 3 different seizure medications which include Lamictal, Keppra and Tegretol.  He has had a very itchy rash that has been spreading over his body for about 6-8 weeks now.  We finally was able to see a Dermatologist this morning and he thinks it may be Lichen Planus.  He did do a biopsy and we will have the results in 10 days.  My question is..... Do you have any knowlege of Lichen Planus being connected with any of the 3 seizure meds that I previously listed that my husband is on?   Also do you know of any other rashes connected to these 3 seizure meds?  Both the Nuerologist and Dermatologist have ruled out Steven Johnson's.  Any help would be greatly apprecaited.  Thank you