Why does dandruff appear because of lice? - briefly
Lice infest the scalp, causing irritation and scratching that accelerates skin cell turnover, producing visible flakes often mistaken for dandruff. The inflammation and possible secondary infection further exacerbate the shedding of dead skin.
Why does dandruff appear because of lice? - in detail
Head lice infest the scalp by feeding on blood and laying eggs close to the skin surface. Their activity irritates the epidermis, triggering a localized inflammatory response. The inflammation increases the turnover of epidermal cells, causing excess keratin to accumulate and shed as visible flakes.
The mechanical movement of lice and their nits also disrupts the natural barrier of the scalp. This disruption allows colonising bacteria and fungi, such as Malassezia spp., to proliferate. Their metabolic by‑products further irritate the skin, amplifying the shedding process.
Key mechanisms linking lice infestation to flaking scalp:
- Mechanical irritation: Chewing and crawling damage hair follicles and skin cells, prompting accelerated desquamation.
- Inflammatory mediators: Histamine and cytokines released in response to bites increase vascular permeability and stimulate keratinocyte proliferation.
- Microbial overgrowth: Disrupted barrier promotes growth of opportunistic microbes that produce irritant lipids, worsening scalp dryness.
- Allergic sensitisation: Repeated exposure to lice saliva can induce hypersensitivity, leading to chronic itching and secondary scaling.
Effective management requires simultaneous treatment of the ectoparasite and the resulting scalp condition. Pediculicidal agents eradicate the insects, while antifungal or anti‑inflammatory shampoos reduce microbial load and soothe inflammation, allowing normal epidermal turnover to resume.