Clinical recognition, management, and research progress of infantile perianal protrusion: a narrative review and literature-based case aggregation

Background Infantile perianal protrusion (IPP) is a benign clinical lesion or phenotype, usually arising from or adjoining the anal verge and occurring predominantly in girls. Although encountered in pediatric practice, it remains underrecognized and may be mistaken for other anal or perianal abnormalities, resulting in unnecessary investigations or treatment. The evidence consists mainly of case reports and small case series. Methods We conducted a narrative review with literature-based case aggregation. A systematic search of PubMed/MEDLINE, Embase, Web of Science, the Cochrane Library, ProQuest, and Scopus was performed from database inception to 30 October 2025, using the principal and historical terms for this lesion, including infantile perianal protrusion , infantile perianal pyramidal protrusion , infantile perineal protrusion , perineal protrusion , perineal nodule , perianal skin tag , anal skin tag , and anal fold , along with their spelling and plural variants. Reference lists of eligible articles were also screened. For included reports, we extracted and analysed data on nomenclature, demographic characteristics, lesion morphology and location, associated conditions, proposed pathogenesis, histopathological and dermoscopic features, management, and outcomes. Potentially overlapping cases were identified on the basis of authorship, institution, recruitment period, and case characteristics, and were counted only once when duplication was likely. Results The literature search identified 169 published patients, comprising 163 children and 6 adult women, with a marked female predominance. Lesions were usually solitary and most commonly located at the anterior anal midline, though posterior, lateral, multiple, and circumferential presentations were also reported. Three subtypes were recognized: constitutional, acquired functional, and lichen sclerosus-associated. Constitutional lesions were typically asymptomatic and often self-resolving. Acquired functional lesions were frequently associated with constipation or local irritation and improved after management of contributing factors. Lichen sclerosus-associated lesions showed characteristic histopathological changes. In non-lichen sclerosus cases, histopathology was generally nonspecific, whereas dermoscopy revealed a recurrent vascular pattern in reported cases. Conclusions IPP is usually a benign anal-verge/perianal clinical lesion with a favorable course. Typical lesions can generally be recognized clinically and managed with reassurance and observation, without routine biopsy, imaging, or excision. Associated conditions—particularly constipation, local irritation, fissuring, dermatitis, fistula, or lichen sclerosus—should be assessed and treated when suggested by the history or examination rather than investigated routinely in every patient. Greater awareness may reduce misdiagnosis and unnecessary intervention.