How are lice dangerous to humans? - briefly
Head and body lice provoke intense itching and skin irritation, and scratching can create lesions that become infected with bacteria. In rare instances they serve as vectors for pathogens such as Rickettsia prowazekii or Bartonella quintana, leading to serious disease.
How are lice dangerous to humans? - in detail
Lice infestations pose several health risks beyond mere irritation. Their bites break the skin, allowing bacterial entry that can cause secondary infections such as impetigo, cellulitis, and erysipelas. Persistent scratching may lead to excoriations, which increase the likelihood of scar formation and pigment changes.
The insects serve as vectors for pathogenic organisms. Body lice (Pediculus humanus corporis) are known carriers of Rickettsia prowazekii, the agent of epidemic typhus, and Bartonella quintana, which causes trench fever. Transmission occurs when infected lice are crushed on the skin or when contaminated feces are scratched into abrasions. Head lice (Pediculus humanus capitis) rarely transmit disease, but heavy infestations can trigger allergic reactions, ranging from localized urticaria to systemic hypersensitivity in susceptible individuals.
Psychological impacts arise from the stigma of infestation. Anxiety, embarrassment, and social withdrawal are documented, particularly among school-aged children and their families. In severe cases, chronic stress may exacerbate existing dermatologic conditions such as eczema or psoriasis.
Control measures must address both the parasites and the environment. Effective strategies include:
- Thorough combing with fine-toothed lice combs to remove live insects and nits.
- Application of approved pediculicides, following manufacturer instructions to prevent resistance.
- Washing clothing, bedding, and personal items at ≥60 °C or sealing them in airtight containers for two weeks to eliminate dormant stages.
- Regular inspection of close contacts to prevent reinfestation.
Early detection and prompt treatment reduce the risk of complications, limit transmission, and minimize the socioeconomic burden associated with outbreaks.