warts are caused by a virus known as human papilloma virus.in beard area they are likely to spread fast due to daily shaving with razor. hence trimming is best option. also it can be transmitted from one person to another by sharing of towel, pillow etc. they are quite frustrating at times and keep in recurring. in such cases immunotherapy plays a vital role in some cases. it induces immunity in the body against the virus and eradicates it .