Anal itching predominantly at night in children

Specialty: Pediatrics.

• Children's anal itching
• suspected oxyuriasis
• nocturnal perineal itching

Why it occurs

• Infection by Enterobius vermicularis or oxyuriasis (female nematodes migrate at night to the perianal area to deposit their eggs, causing an intense local allergic reaction due to the viscous liquid that surrounds them)
• Perianal irritant contact dermatitis (poor hygiene with accumulation of fecal remains, or excessive washing with scented soaps and wipes that alter the skin barrier)
• Perianal streptococcal infection (caused by Streptococcus pyogenes, presents with bright red, well-defined perianal erythema, pain with defecation and anal fissures)
• Atopic dermatitis or anal eczema (localized manifestation of constitutional atopy exacerbated by continuous scratching)
• Alternative intestinal parasitosis (such as Giardia lamblia, although anal itching is less characteristic than the digestive symptoms)

Initial workup

Graham test or transparent adhesive tape test (should be performed in the morning before the child defecates or bathes, pressing adhesive tape on the perianal folds and placing it on a slide for microscopic examination in search of asymmetric pinworm eggs, repeated 3 consecutive days to increase sensitivity). Direct visual examination of the perianal area at night or early in the morning with a flashlight to detect moving white threadlike worms. Perianal swab smear or culture if perianal streptococcal infection is suspected.

Standard management

• Mebendazole — antiparasitic of choice; single dose of 100 mg orally for any age over 12-24 months; A second identical dose must be repeated after 2 weeks because the drug does not destroy the eggs, thus avoiding autoinfection.
• Pyranthine pamoate — effective alternative; single dose of 11 mg/kg orally, maximum 1 g, also to be repeated in 2 weeks
• Albendazole — another alternative; single dose of 400 mg orally in children over 2 years of age, or 200 mg in children 12 to 24 months, to be repeated after 2 weeks
• Mupirocin 2% ointment or topical fusidic acid (indicated if there is suspicion of bacterial superinfection due to scratching; apply 2-3 times a day for 5-7 days). Mandatory simultaneous treatment for all cohabitants of the house.