Impetigo DOES itch.
More Info: Itching is a primary symptom of impetigo. Depending on the type of impetigo, other symptoms and signs that may include red sores that crust over, small blisters filled with fluid, pus-filled sores that turn into ulcers. (1)
Don’t Scratch the Itch!
Though itching is a possible symptom of impetigo, not all who suffer from the skin infection experience itching. If you are itchy, it is important not to scratch the area as scratching can spread the infection further. As a bacterial infection, any time that you pick at or scratch the eruptions caused by impetigo, you are making the area more susceptible to further bacterial invasion. 
Further, scratching can introduce dirt and foreign matter to the open wound as well as tear the skin, which may lead to permanent scarring. 
 “Impetigo: Symptoms – MayoClinic.com.” Mayo Clinic. N.p., n.d. Web. 5 Mar. 2012. http://www.mayoclinic.com/health/impetigo/DS00464/DSECTION=symptoms
 “Impetigo ” Ask Dr. Sears®. N.p., n.d. Web. 5 Mar. 2012. <http://www.askdrsears.com/topics/skin-care/impetigo>.
 “Impetigo .” KidsHealth – the Web’s most visited site about children’s health. N.p., n.d. Web. 5 Mar. 2012. <http://kidshealth.org/teen/infections/skin_rashes/impetigo.html#>