Lice life cycles

Health Services Guidelines 

Student Health Services Department of Fresno Unified School District implemented guidelines which are consistent with practices supported by scientific information regarding head lice.  Head lice are a nuisance condition and pose no threat to a student’s health.  Therefore, to protect students from unnecessary exclusion from school, those students with suspected infestations of head lice will be assessed and referred for treatment as follows: 


An active head lice infestation shall be defined as the presence of a live (crawling) louse on the student’s head or facial hair.  

School personnel trained by the credentialed school nurse will screen students who present with symptoms that include the presence of a moving louse and / or persistent scalp itching.  Students who present with lice eggs (nits) only are not automatically presumed to have an active lice infestation and will not be considered to have a lice infestation unless a live (crawling) louse is found on the head. 

Every effort will be made to protect the student’s privacy and maintain confidentiality.  
(cf. 4119.23/4219.23– Unauthorized Release of Confidential/Privileged Information) 

The student will be screened by separating the hair shafts with clean applicator sticks and systematically checking the entire scalp. The presence of a crawling louse will be diagnostic for head lice. 
(cf. 5141.3 – Health Examinations) 

“Head lice rarely (if ever) cause direct harm, and they are not known to transmit infectious agents from person-to-person.  Thus, they should not be considered as a medical or a public health problem.  There is no convincing data that demonstrates that exclusion policies are effective in reducing the transmission of lice.  It is our professional opinion that the no-nits policies are based on misinformation rather than on objective science. ”Pollack, Richard J., 2000, Head Lice Information Statement, Harvard School of Public Health website:

Referral for Treatment

A student with an active head lice infestation will receive a written referral requesting the parent/guardian to follow-up with an appropriate treatment at home.  A student will not be referred for treatment unless at least one live (crawling) louse is identified.  Students will not be referred for treatment with the presence of nits only. Students may remain in school until the end of the school day. 
Students with active infestations must be treated before returning to school. 

(Education Code 48213) (cf. 5112.2 – Exclusions from Attendance) (cf. 5145.6 – Parental Notifications) 


Effective lice treatment is defined as removing living lice.  The removal of nits and egg casings is not required to prevent transmission of lice to other students.  Nit removal is advised for cosmetic reasons or to help prevent misdiagnosis but is not required for re-entry into school.  Lice treatments with documented effectiveness are listed below.  Students must be treated at home using one or more of these methods before a student will be cleared for return to school.  Fresno Unified School District does not give preference for any of the methods listed.  The goal is removal of the live lice in a way that is safe for the student.  The school nurse may be consulted by parents for additional treatment suggestions: 
a) Manual removal of live head lice 
b) Wet combing:   Go through hair sections from the scalp to the end of the hair. Nits are usually found close to the scalp. Dip the comb in a cup of hot, soapy water or use tape to remove lice, nits or debris from the comb. Sift through the same section of hair and look for attached nits and live lice. Move on to the next section until the entire scalp and all hair has been checked.  Check the scalp of the infested child every day for 10 days and regularly thereafter. If additional nits (at least 3-5 per day) are discovered, another manual search is recommended. 
c) Treat with permethrin 1% or pyrethrin 0.33% solution (RID, Nix, generic brands, etc.) according to label instructions.  Label directions must be followed exactly for effective elimination of hatched lice.  Current literature advises repeating the treatment in 7-10 days if live lice remain. 

Return to School 

Students can be effectively treated and returned to school with no more than one day of absence.  Students are considered to have been treated when no live (crawling) louse is found upon re-examination of the scalp by designated trained school personnel.  The presence of nits (eggs) alone does not constitute failure to treat and is not grounds for continued exclusion from school. 
Reichert, Mackenzie, Hightower and Blake (2001) found that the presence of nits did not imply an ongoing active infestation with lice; on initial screening, only 31% of children with nits had lice.  Furthermore, not all children with nits became infested; only 18% of children with nits alone developed lice over the next 14 days.  Most children with nits alone will not become infested.  Excluding these children from school and requiring them to be treated with a pediculicide is excessive.  Pediatrics.  2001; 107:1011-1015. ​

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