Pediculosis capitis
Clinical Presentation
- Cardinal symptom: pruritus, erythema, secondary impetiginization from scratching.
- Eggs (nits): attached to the hair shaft in chitin shell (yellowish); viable nits near the scalp, empty shells further distally.
- Head louse: retroauricular + neck, often cervical lymphadenopathy.
- Body louse: excoriated maculopapules on the trunk (shoulders, back, hips); chronic → hyperpigmentation ("vagabond's skin").
- Pubic louse: maculae caeruleae (bluish-gray spots) at bite sites are regarded as the classic sign — but they are frequently absent (short infestation, fair skin type, after shaving); neither practice photograph shows them. Proof comes from lice and nits on the terminal hairs, not from the blue macule.
Diagnostics
- Clinical + wet combing (gold standard for head lice): comb wet hair with a fine-toothed louse comb.
- Dermatoscopy: viable nits with intact embryo directly on the hair shaft.
- Vector detection of the body louse in the seams of clothing.
Environmental & General Measures
- Wash bed linen/towels/caps at ≥ 60 °C or store in sealed plastic bags for at least 3 days at room temperature.
- Clean combs/brushes in hot soapy water.
- Co-treatment of close contacts; children may return to community facilities after the first effective treatment (notification duty in Germany under §34 IfSG for institutions).
Differential diagnoses
- Scabies
- Cimicosis (bed bug bites)
- Urticaria papulosa
- Folliculitis (infectious)
- Tinea cruris
- Condylomata acuminata (genital warts)
- Allergic contact dermatitis
- Impetigo
Practise Pediculosis capitis in the app
Flashcards with spaced repetition, exam questions and spot-the-diagnosis on this topic – in DermaFuchs, free of charge.
In the DermaFuchs app: 1 flashcards · 6 clinical images
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Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.