The primary purpose of the study is to evaluate safety and tolerability of a single application of Ha44 Gel 0.74% w/w for the treatment of head lice. Secondary purpose is to evaluate PK of Ha44 and benzyl alcohol under conditions of maximal exposure in pediatric population.

Inclusion Criteria:

1. Male or female, 6months < 3years of age
2. Good health
3. Active head lice infestation defined as the presence of at least 3 live lice
4. Dermatological condition of scalp (at least G2 erythema or pruritus with evidence of excoriation/inflammation)
5. Parent/guardian agrees to allow PK samples collected
6. Signed Informed Consent Form

Exclusion Criteria:

1. Condition or illness that in the opinion of the investigator may interfere with the study results.
2. Current dermatological disease that may compromise the health of subject or the assessment of safety. Subjects with scalp ulceration or evidence of scalp infection should not be enrolled.
3. Prior reaction to product containing piperonyl butoxide, pyrethrin, or pyrethrum extract.
4. Receiving systemic or topical medication that may interfere the study results.
5. Received an investigational agent within 30 days prior to Day 0.