Pediculosis infestation

Pediculosis infestation includes head lice (Pediculus capitis) and body lice (Pediculus humanus). Adult lice and nits are easily visible. Find body lice in seams of clothing. Head lice are most common in children ages 3-12 years in the U.S. Lice are spread by person-to-person contact.

CASES/YEAR
9,000,000 (US); 180,000,000 (Global)
CATEGORY
Person-To-Person
AGENT TYPE
Other
OTHER NAMES
Head lice (Pediculus capitis); Body lice (Pediculus humanus);
ACUITY
Acute-Moderate
INCUBATION
Eggs: 7-10 days under optimal conditions; Nymphs: 9-12 days; The egg-to-egg cycle is about 3 weeks. The adult life cycle is about 1 month; [CCDM]
INITIAL SYMPTOMS
Nits in hair or clothing; Itching;
PRECAUTIONS
Contact until 24 hours after initiation of effective therapy; [CDC 2007 Guideline for Isolation Precautions] "Under suitable environmental conditions, head and crab lice eggs can remain viable away from the host for up to 7-10 days; body lice eggs remain viable for up to a month." [CCDM, p. 447]
COMMENTS
Pediculosis is infestation by human head or body lice. Empty eggs (nits) remain attached to hair or clothing for months after hatching. Patients may become sensitized to lice saliva and have itching. Lice are spread by person-to-person contact. [Harrisons, p. 638] Lice can survive away from the body for 10 days. [ABX Guide] Body lice infest the poor, homeless, and immunocompromised, particularly those with AIDS. Infections carried by body lice include relapsing fever, trench fever, and epidemic typhus. Skin manifestations include erythematous papules and papular urticaria. [PPID, p. 3482-4] Blue macules (maculae ceruleae) develop at bite sites. [Cecil, p. 692] Secondary infection can cause lymphadenitis, especially cervical. [CCDM, p. 446]
DIAGNOSTIC
Clinical; Adult lice and nits are easily visible; Find body lice in seams of clothing; Head lice most common in children ages 3-12 years in the U.S. [ABX Guide] Wood's lamp: live nits fluoresce; [Merck Manual, p. 1058]
SCOPE
Global
SIGNS & SYMPTOMS
  • H lymphadenopathy
  • S entry wound with lymph nodes
  • S lymphadenitis, acute
  • S papules or plaques
  • S urticaria
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Skin or Mucous Membranes (Includes Conjunctiva)
SOURCE
Person-to-Person
RESERVOIR
Human
RISK FACTORS
TREATMENT
For body lice, treat the clothes, not the patient. Machine wash with hot water and then iron seams. [ABX Guide: Lice]
DRUG LINK
Merck Manual: Lice
REFERENCES FOR CASES/YEAR
1. (US) 6-12 million children with head lice every year in the US; [Cecil, p. 691]
2. (Global) Body lice are common in war, refugee camps, and among the urban homeless. Calculate: global cases/yr = 20 X US cases/yr = 180 million;