# Infantile Hemangiomas: When to Treat and When to Watch

## Introduction

Infantile hemangiomas (IH) are the most common benign vascular tumors of infancy, occurring in approximately 4-5% of all infants. They follow a characteristic lifecycle of proliferation, plateau, and involution. The critical clinical challenge lies in distinguishing lesions that will involute harmlessly from those requiring early intervention to prevent functional impairment, disfigurement, or life-threatening complications.

## Epidemiology and Risk Factors

Infantile hemangiomas are more common in **female infants** (3:1 ratio), **premature infants** (particularly those under 1500 g birth weight), **Caucasian** infants, and those born to mothers with **preeclampsia** or **placenta previa**. Multiple gestations and advanced maternal age are additional risk factors. Most IH are not present at birth, though a **precursor lesion** such as a pale macule, telangiectatic patch, or bruise-like area may be noted at birth and foreshadow the hemangioma that will emerge in the following weeks.

## Pathogenesis

Infantile hemangiomas arise from clonal proliferation of **GLUT-1 positive** endothelial cells. GLUT-1 positivity is the hallmark immunohistochemical marker that distinguishes IH from other vascular tumors and vascular malformations. Proposed theories of origin include **placental embolization** (supported by the shared GLUT-1 expression between IH and placental tissue) and somatic activating mutations in the **VEGF/PI3K/AKT/mTOR signaling pathway**. The proliferating phase is characterized by high levels of **VEGF-A**, **bFGF**, and **MMP-9**. Involution occurs through apoptosis, with progressive replacement of the vascular tumor by **fibrofatty tissue**.

## Natural History and Growth Phases

### Proliferative Phase (0-12 months)

Rapid growth typically begins at 1 to 3 weeks of age, with the most rapid growth occurring between 1 and 3 months. Approximately **80% of growth** is completed by 5 months of age for superficial IH. Deep IH may have a later and more prolonged proliferative phase, extending up to 12 to 18 months.

### Plateau Phase (12-18 months)

During this period, the lesion shows minimal growth or change and remains stable in size and color.

### Involution Phase (1-10 years)

Gradual regression occurs at a rate of approximately **10% per year**, with 50% involuted by age 5, 70% by age 7, and 90% by age 9. **Residual changes** persist in up to 50 to 70% of cases and may include telangiectasias, fibrofatty tissue, anetoderma, and redundant skin.

## Classification

IH are classified by depth and morphology. **Superficial IH** (60%) are bright red, well-defined, and have a "strawberry" appearance, being limited to the papillary dermis. **Deep IH** (15%) present as blue-violaceous, compressible nodules with overlying normal or slightly discolored skin, extending into the reticular dermis and subcutis. **Mixed IH** (25%) combine superficial and deep components. Morphologic subtypes include focal (localized), segmental (plaque-like, following a developmental segment), indeterminate, and multifocal.

<image>Clinical progression photographs showing an infantile hemangioma through its lifecycle: precursor lesion at birth, proliferative phase at 3 months, and involuted phase at age 5 with residual fibrofatty tissue</image>

## When to Watch: Observation Criteria

Observation is appropriate for small, focal, uncomplicated IH in non-critical locations such as the trunk and extremities, when there is no evidence of ulceration, functional impairment, or rapid growth, and the morphology is non-segmental. Parent education regarding the expected natural course and warning signs is essential. Serial photography and clinical follow-up every 2 to 4 weeks during the proliferative phase allow for timely identification of any change in trajectory.

## When to Treat: Indications for Intervention

### High-Risk Features Requiring Early Treatment

Several locations and features mandate early treatment. **Airway hemangiomas** in the beard distribution (mandibular V3 segment) carry a 60% risk of subglottic involvement. **Periocular IH** risk amblyopia, astigmatism, and strabismus from mechanical ptosis or direct pressure on the globe. **Nasal tip ("Cyrano") IH** can cause cartilage destruction and permanent nasal deformity. **Lip IH** carry risks of ulceration, feeding difficulty, and cosmetic disfigurement. **Large segmental facial IH** should prompt evaluation for **PHACE syndrome** (Posterior fossa anomalies, Hemangiomas, Arterial anomalies, Cardiac defects, Eye anomalies). **Lumbosacral IH** should be evaluated for **LUMBAR syndrome** (Lower body hemangioma, Urogenital anomalies, Myelopathy, Bony deformities, Anorectal malformations, Arterial anomalies, Renal anomalies). **Ulcerated IH** present risks of pain, bleeding, infection, and scarring. When **multifocal IH** (more than 5 lesions) are present, screening for hepatic hemangiomas with abdominal ultrasound is indicated.

<image>Anatomical diagram of the infant face showing high-risk locations for infantile hemangiomas including periocular, nasal tip, lip, and beard distribution areas with annotations of associated complications</image>

## Treatment Modalities

### First-Line: Oral Propranolol

**Propranolol** at 2 to 3 mg/kg/day divided into two to three doses is the standard of care since the landmark 2008 discovery by Leaute-Labreze et al. Its mechanism involves vasoconstriction (producing an immediate visible effect), decreased VEGF and bFGF expression, and induction of endothelial apoptosis. Treatment should ideally begin at **1 to 2 months of age** during the early proliferative phase. Pre-treatment evaluation includes heart rate, blood pressure, and cardiac auscultation, with echocardiogram if PHACE syndrome is suspected. Adverse effects include bradycardia, hypotension, hypoglycemia (parents should be instructed to feed regularly), bronchospasm, sleep disturbance, and cold extremities. Treatment duration is typically 6 to 12 months, with a taper over 2 to 4 weeks to avoid rebound growth.

### Topical Timolol

**Timolol maleate 0.5% gel-forming solution** applied twice daily is useful for thin, superficial IH where systemic therapy is not warranted. It is appropriate for small, non-critical superficial IH. In premature or low-birth-weight infants, monitoring for systemic absorption is important.

### Surgical and Procedural Options

**Pulsed dye laser (PDL)** is effective for residual telangiectasias, superficial IH, and ulcerated lesions. **Surgical excision** is reserved for residual fibrofatty tissue, pedunculated lesions, or IH unresponsive to pharmacotherapy. **Intralesional corticosteroids** have been largely supplanted by propranolol but are still occasionally used for focal periocular IH.

### Management of Ulcerated IH

Wound care includes barrier creams, non-adherent dressings, and topical antibiotics. Pain control involves acetaminophen and topical lidocaine. Oral propranolol accelerates healing of ulcerated IH, and pulsed dye laser can provide pain relief and promote re-epithelialization.

| Treatment | Indication | Mechanism | Key Considerations |
|-----------|-----------|-----------|-------------------|
| Oral propranolol (2–3 mg/kg/day) | First-line for IH requiring treatment | Vasoconstriction, decreased VEGF, apoptosis | Start at 1–2 months; monitor HR/BP/glucose |
| Topical timolol 0.5% | Small, thin superficial IH | Local beta-blockade | Avoid in premature infants |
| Pulsed dye laser | Residual telangiectasias; ulcerated IH | Selective photothermolysis | Multiple sessions required |
| Surgical excision | Residual fibrofatty tissue; pedunculated | Definitive removal | Usually deferred until after involution |
| Intralesional corticosteroids | Focal periocular IH (select cases) | Anti-inflammatory | Largely supplanted by propranolol |

<image>Flowchart algorithm for management of infantile hemangiomas showing decision points based on location, size, complications, and treatment options from observation through propranolol to surgical intervention</image>

## Key Clinical Pearls

GLUT-1 immunostaining is the definitive marker distinguishing IH from congenital hemangiomas (RICH, NICH, PICH) and vascular malformations. Propranolol should be initiated early, ideally before 3 months of age, during the proliferative phase for maximum efficacy. Beard distribution segmental IH mandates airway evaluation even in the absence of respiratory symptoms. Not all hemangiomas involute to a cosmetically acceptable result, and realistic expectations should be set with parents regarding potential residual changes. Five or more cutaneous IH should prompt hepatic ultrasound screening.

## References

1. Leaute-Labreze C, Hoeger P, Mazereeuw-Hautier J, et al. A randomized, controlled trial of oral propranolol in infantile hemangioma. *N Engl J Med*. 2015;372(8):735-746.
2. Krowchuk DP, Frieden IJ, Mancini AJ, et al. Clinical practice guideline for the management of infantile hemangiomas. *Pediatrics*. 2019;143(1):e20183475.
3. Darrow DH, Greene AK, Mancini AJ, Nopper AJ. Diagnosis and management of infantile hemangioma. *Pediatrics*. 2015;136(4):e1060-e1104.
4. Metry D, Heyer G, Hess C, et al. Consensus statement on diagnostic criteria for PHACE syndrome. *Pediatrics*. 2009;124(5):1447-1456.