Lice are host specific, permanent parasites which cause [[Parasitic skin infections - Pathology#Lice|pediculosis]]. The louse saliva and faeces contain allergenic substances which cause irritation, rubbing, licking and skin damage leading to decreased host productivity. | Lice are host specific, permanent parasites which cause [[Parasitic skin infections - Pathology#Lice|pediculosis]]. The louse saliva and faeces contain allergenic substances which cause irritation, rubbing, licking and skin damage leading to decreased host productivity. |