Those Lousy Bugs

Controversies and misunderstandings regarding head lice diagnosis and treatment are addressed in this thorough publication.  Some are summarized here:

Can a child get head lice from furniture or sharing a hat?  Head lice cannot survive long without a host beyond 6-20 hours.  Head lice are rarely if ever transmitted via furniture but may be transferred through brushes, pillows, towels or hats, if shared immediately.  Main route of transmission remains head-to-head contact.  Never disallow helmet use because of fear for head lice.  It is unnecessary to scour the house or to spray insecticides.  Vacuuming of furniture and car seats is adequate.  Hot water washing of pajamas, bed linens and towels used within 2 days of treatment is a good idea, as is dry cleaning of non-washable items.  Soak brushes and combs in either alcohol or in dish detergent and hot water for one hour. 

Can head lice develop resistance to therapy? Resistance to certain therapies may have always existed.  Treatment failures stem from using treatments improperly or from reinfestation.  Resistance to one class of therapy (e.g., pyrethrins such as A-200 or RID) is often associated with sensitivity to another class of therapy (e.g., permethrins such as Nix). 

How to overcome common mistakes when applying therapy.  Apply permethrin to damp, towel-dried hair - not wet hair (which will dilute the pediculocide).  Apply pediculocides a few drips at a time, directly on the scalp, section by section - not as one would apply a regular shampoo.  Be certain scalp and roots are saturated.  Extra bottles of pediculocide may be required for very thick or very curly hair.  Time treatments only after pediculocides have been applied to all areas.  All affected house members must be checked and treated.

Be sure of diagnosis.  Of people who think they have head lice, 42% have neither lice nor eggs.  Teachers' correctly diagnose current or past infestation 85% of time, but only half of these are actually active cases.  Of all nurse-diagnosed head lice cases, only 32% are actually active infestations.  Of all physician-diagnosed head lice cases, only 12% are actually active infestations. 

Dispel common myths.  Head lice do not result from poor hygiene or dirty living conditions.  Head lice can not jump from person to person.  Head lice do not carry disease.  Head lice do not breed in furniture.  Head lice do not prefer long hair.

(Burgess IF et al:  Postgrad Instit for Med. June 2003) -  H.T.