Scalp Mycobiota Alterations Associated with Pediculosis: A Case–Control Study

Abstract

Pediculosis is one of the most common ectoparasitic infestations of school-age children worldwide. While numerous clinical features have been described, little is known about its effect on the scalp mycobiome. The study aims to determine whether active Pediculosis is associated with changes in scalp fungal colonization and diversity. From April to July 2025, a case-control study was conducted in primary schools in Nineveh, Iraq. A total of 100 female children were recruited, of whom 50 were head louse-infested, and 50 were louse-free controls. Scalp swabs were cultured on Sabouraud dextrose agar. Fungal isolates were identified by morphology and confirmed by PCR and Sanger sequencing. Fungal growth was significantly lower in patients with pediculosis compared with controls (34.0% vs. 78.0%; χ² = 19.64, p < 0.001). Patients had an 85% lower likelihood of fungal growth compared to controls (OR = 0.15, 95% CI: 0.06–0.35), whereas controls had markedly higher odds of a positive culture (OR = 6.88, 95% CI: 2.82–16.74). Culture-negative specimens were approximately three times more frequent in the patient group (66.0% vs. 22.0%). Fungal diversity was substantially lower among children with infestation. Penicillium chrysogenum predominated in controls (30.0%) but was markedly suppressed in patients (6.0%). Neoscytalidium hyalinum, an emerging dermatological and systemic pathogen, was identified exclusively among patients with louse infestation. Active pediculosis is strongly associated with reduced scalp fungal colonization and lower scalp fungal diversity. These findings suggest that head lice infestation may alter the scalp microenvironment in a manner unfavorable to fungal growth.

Keywords

• Pediculosis
• Head lice
• Scalp mycobiome
• Scalp mycobiota
• Fungal colonization.

Pedikülozis ile İlişkili Saçlı Deri Mikobiyotasındaki Değişiklikler: Bir Vaka–Kontrol Çalışması

Abstract

Pedikülozis, dünya genelinde okul çağındaki çocuklarda görülen en yaygın ektoparaziter infestasyonlardan biridir. Çok sayıda klinik özelliği tanımlanmış olmasına rağmen, pedikülozisin saçlı deri mikobiyomu üzerindeki etkileri hakkında sınırlı bilgi bulunmaktadır. Bu çalışma, aktif pedikülozisin saçlı derideki fungal kolonizasyon ve çeşitlilikte değişikliklerle ilişkili olup olmadığını belirlemeyi amaçlamaktadır. Nisan–Temmuz 2025 dönemleri arasında Irak’ın Ninova ilindeki ilkokullarda bir vaka–kontrol çalışması yürütülmüştür. Toplam 100 kız çocuk çalışmaya dâhil edilmiş olup bunların 50’sinde baş biti infestasyonu saptanmış, 50’si ise bit enfestasyonu olmayan kontrol grubunu oluşturmuştur. Saçlı deriden alınan sürüntü örnekleri Sabouraud dekstroz agarda kültüre edilmiştir. Fungal izolatlar morfolojik yöntemlerle tanımlanmış ve PCR ile Sanger dizileme yöntemleriyle doğrulanmıştır. Fungal üreme, pedikülozisli hastalarda kontrol grubuna kıyasla anlamlı derecede daha düşük bulunmuştur (%34,0’a karşı %78,0; χ² = 19,64, p < 0,001). Pedikülozisli bireylerde fungal üreme olasılığı kontrollerle karşılaştırıldığında %85 daha düşük bulunmuştur (OR = 0,15; %95 GA: 0,06–0,35), buna karşılık kontrol grubunda pozitif kültür elde edilme olasılığı belirgin şekilde daha yüksek saptanmıştır (OR = 6,88; %95 GA: 2,82–16,74). Kültür negatif örnekler hasta grubunda yaklaşık üç kat daha sık gözlenmiştir (%66,0’a karşı %22,0). Fungal çeşitlilik, infestasyonu olan çocuklarda belirgin derecede daha düşüktür. Penicillium chrysogenum kontrol grubunda baskın tür olarak (%30,0) saptanırken, hasta grubunda belirgin şekilde baskılanmıştır (%6,0). Gelişmekte olan dermatolojik ve sistemik bir patojen olan Neoscytalidium hyalinum ise yalnızca bit infestasyonu bulunan hastalarda tanımlanmıştır. Aktif pedikülozis, saçlı deride fungal kolonizasyonun azalması ve fungal çeşitliliğin düşmesi ile güçlü bir şekilde ilişkilidir. Bu bulgular, baş biti infestasyonunun saçlı deri mikrohabitatını mantar üremesi açısından elverişsiz hâle getirebileceğini düşündürmektedir.

Keywords

• Pedikülozis
• Baş biti
• Saçlı deri mikobiyomu
• Saçlı deri mikobiyotası
• Fungal kolonizasyon.

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