Infantile hemangioma with minimal or arrested growth (IH-MAG) is a subtype of infantile hemangioma that shows little or no obvious growth during infancy. Although these lesions may appear less active than classic infantile hemangiomas, some may still be associated with ulceration, functional risk, permanent disfigurement, or structural anomalies.

This prospective observational cohort study will compare infants with IH-MAG and infants with classic infantile hemangioma at their first specialist evaluation. Each participant will undergo routine clinical assessment, standardized photography, risk classification according to the 2019 American Academy of Pediatrics guideline, and Hemangioma Severity Scale scoring. The main outcome is the initial management recommendation after specialist assessment, categorized as active management or treatment versus observation. The study will not assign any treatment. All management recommendations will be made by clinicians according to routine clinical practice and guideline-based assessment.

Infantile hemangioma with minimal or arrested growth (IH-MAG) is a distinct clinical subtype of infantile hemangioma characterized by early-onset vascular lesions with minimal or absent proliferative growth. IH-MAG may be mistaken for capillary malformation or other vascular anomalies because of its relatively subtle growth pattern. However, some IH-MAG lesions, particularly segmental lesions or lesions in high-risk anatomic sites, may still be associated with ulceration, functional impairment, permanent disfigurement, or syndromic structural anomalies.

Standardized tools, including the 2019 American Academy of Pediatrics risk classification and the Hemangioma Severity Scale, are widely used to assess risk and severity in infantile hemangioma. Their clinical value has been studied in infantile hemangiomas overall, but their distribution and decision-making value in IH-MAG remain insufficiently defined.

This is a single-center, prospective, observational comparative cohort study. Infants aged 12 months or younger who present for their first systematic evaluation at a hemangioma specialty clinic will be enrolled if they are clinically diagnosed with IH-MAG or classic infantile hemangioma and meet the eligibility criteria. Participants will be assigned to two observational cohorts: an IH-MAG cohort and a classic infantile hemangioma cohort. No treatment will be assigned by the study protocol.

At baseline, demographic information, lesion characteristics, standardized clinical photographs, AAP risk category, Hemangioma Severity Scale score, and the clinician's initial management recommendation will be recorded. The primary outcome is the initial management recommendation after the first specialist assessment, categorized as active management or treatment versus observation. Active management may include topical therapy, systemic therapy, laser therapy, surgery, local treatment, imaging evaluation, specialist referral, or multidisciplinary assessment when clinically indicated. Observation refers to regular follow-up, parental education, photographic monitoring, and risk counseling without active treatment or additional active management at baseline.

Secondary outcomes include the distribution of AAP risk categories, Hemangioma Severity Scale scores, treatment intensity, reasons for treatment recommendation, use of imaging or specialist screening, changes in the management plan during follow-up, and diagnostic reclassification of suspected IH-MAG. Follow-up information will be collected at approximately 1, 3, and 6 months after baseline to document management implementation, lesion changes, complications, treatment adjustment, and diagnostic stability.

Inclusion Criteria:

• Infants clinically diagnosed with infantile hemangioma, including minimal or arrested growth infantile hemangioma and classic infantile hemangioma.
• Participants undergoing their initial specialist evaluation at the study center.
• Age at baseline: from birth to 24 months.
• Sufficient clinical information available for baseline assessment, including lesion location, morphology, size, number of lesions, complications, and treatment recommendation.
• Parents or legal guardians are able to understand the study procedures and provide written informed consent.

Exclusion Criteria:

• Patients with vascular anomalies other than infantile hemangioma, including vascular malformations, congenital hemangioma, kaposiform hemangioendothelioma, pyogenic granuloma, or other vascular tumors.
• Patients with insufficient clinical information to determine the infantile hemangioma subtype, AAP risk category, Hemangioma Severity Scale score, or baseline treatment recommendation.
• Patients who have received systemic pharmacologic treatment, procedural treatment, laser therapy, or surgical treatment for infantile hemangioma before the baseline specialist evaluation.
• Patients with severe comorbidities or unstable medical conditions that may interfere with clinical assessment or follow-up.
• Parents or legal guardians who decline participation or are unable to provide informed consent.

Infants aged 12 months or younger who present for their first systematic evaluation at a hemangioma specialty clinic and are clinically diagnosed with either infantile hemangioma with minimal or arrested growth or classic infantile hemangioma. Participants will be enrolled prospectively and followed as two observational cohorts.