Trying to Keep Ahead of Lice: A Therapeutic Challenge

C. E. Malcolm, MD, CCFP; J. N. Bergman MD, FRCPC


Skin Therapy Letter. 2006;11(10):1-6. 

In This Article

Clinical Presentation

Although some children with infestation are asymptomatic, the most common symptom is pruritus, which occurs due to sensitization to either louse salivary or fecal antigens and may be so intense that excoriations and secondary bacterial infection may occur.[5]

Many children with an active infestation will, on exam, have nits attached to their hair and some live lice on their scalp. The diagnostic gold standard for head lice is finding a live louse or nymph on the scalp or a viable egg attached to the hair.[5] Nits alone are not proof of active infection because some of these represent hatched empty shell casings or nonviable eggs that may retain a viable appearance for weeks after death. Microscopic examination of the nit, or use of a hand lens, may aid in this determination.[4] Since lice move rapidly, not finding a louse does not completely rule out infestation. The use of louse combs increases the diagnostic yield.[3] If head lice is diagnosed, then it should be treated, since established infestations, in general, do not spontaneously resolve.


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