What can be contracted from lice bites? - briefly
Lice bites can introduce bacterial pathogens such as Rickettsia prowazekii (epidemic typhus), Borrelia recurrentis (relapsing fever), and Bartonella quintana (trench fever), and they may also lead to secondary skin infections.
What can be contracted from lice bites? - in detail
Louse bites can lead to several medical conditions, most of which arise from the skin’s reaction to the bite or from secondary infection introduced by scratching.
The immediate response is a localized inflammatory reaction. The bite’s puncture site releases saliva that contains anticoagulant proteins, provoking itching, erythema, and edema. Persistent scratching breaks the epidermal barrier, allowing skin‑resident bacteria to invade deeper tissues.
Common bacterial complications include:
- Impetigo – superficial infection caused by Staphylococcus aureus or Streptococcus pyogenes, presenting as honey‑colored crusted lesions.
- Cellulitis – diffuse, painful swelling of the dermis and subcutis, typically due to S. aureus or β‑hemolytic streptococci, characterized by warmth, redness, and potential fever.
- Erysipelas – acute, well‑demarcated erythema with raised borders, most often linked to group A streptococci.
- Folliculitis – inflammation of hair follicles that may progress to abscess formation if S. aureus proliferates.
Allergic responses range from mild urticaria to severe hypersensitivity. Some individuals develop papular urticaria, a chronic pruritic eruption that recurs with repeated exposure to louse saliva.
Systemic louse‑borne diseases are primarily associated with body lice (Pediculus humanus corporis). When head lice (Pediculus humanus capitis) are involved, transmission of serious pathogens is rare, but the following agents are known to be carried by body lice and can, in theory, be transferred through extensive infestation:
- Epidemic typhus – caused by Rickettsia prowazekii; symptoms include high fever, rash, and severe headache.
- Trench fever – caused by Bartonella quintana; presents with recurrent fever, headache, and leg pain.
- Louse‑borne relapsing fever – caused by Borrelia recurrentis; characterized by episodes of high fever and chills.
Diagnosis relies on clinical assessment of skin lesions and, when systemic infection is suspected, laboratory testing for specific pathogens. Treatment protocols include topical or oral antibiotics for bacterial skin infections (e.g., mupirocin, cephalexin, or clindamycin) and antihistamines or corticosteroids for allergic inflammation. In cases of confirmed louse‑borne disease, appropriate antimicrobial therapy (doxycycline for typhus, azithromycin for trench fever) is required.
Effective control of the infestation—mechanical removal, thorough combing, and application of approved pediculicidal agents—reduces the risk of both cutaneous and systemic complications. Prompt medical evaluation of any worsening or atypical lesion mitigates progression to more serious disease.