The wealthy don't have them and the poor anyways have them....
We don't find that Pharaoh asked Moshe to daven for the removal of the plague of Lice, as he had done by the previous plague of Frogs. The reason was that the lice only affected areas covered with dirt. Pharaoh and his ministers lived in houses covered with marble, and the floor was swept on a daily basis to prevent any dirt that would spread the lice. On the other hand, the poor people who lived in areas covered with dirt were anyways accustomed to dealing with lice on a regular basis (although, the plague of Lice was undoubtedly more severe than the usual bout of lice). Therefore, there was no compelling reason for Pharaoh to ask Moshe to daven for him to have the lice removed (Chizkuni).
