Infantile hemangiomas are benign growths of blood vessel cells that appear as red or purple marks on the skin. While many of these growths shrink and fade on their own, some can cause problems due to their size or location. If a hemangioma interferes with functions like vision or breathing, or is at risk for ulceration and disfigurement, treatment may be recommended. The primary medication used is propranolol, which is highly effective in reducing the size and color of these vascular growths.
How Propranolol Works on Hemangiomas
Propranolol is a beta-blocker drug, initially developed for heart conditions, whose effectiveness for hemangiomas was discovered by chance. It is thought to work through a combination of actions that target the abnormal blood vessels. These mechanisms work together to halt the tumor’s growth and accelerate its natural regression process.
The most immediate effect of propranolol is vasoconstriction, the narrowing of blood vessels within the hemangioma. It accomplishes this by inhibiting the release of nitric oxide, a molecule that helps keep blood vessels dilated. By reducing blood flow, the hemangioma often appears lighter in color, sometimes within a few days of starting treatment.
Propranolol also works to stop the hemangioma from growing further by interfering with growth signals like vascular endothelial growth factor (VEGF). By blocking these signals, the medication cuts off the instructions telling endothelial cells to create more blood vessels. This inhibition of cell proliferation halts the tumor’s development during its rapid growth phase.
The long-term effect involves inducing apoptosis, a form of programmed cell death, in the endothelial cells. Propranolol appears to trigger this self-destruction pathway within the hemangioma’s cells, causing the tumor to shrink and regress. This cellular-level action contributes to a lasting reduction in the hemangioma’s size.
The Treatment Process with Propranolol
Propranolol treatment is available in two main forms. The oral formulation, a liquid syrup, is reserved for larger, deeper, or complicated hemangiomas, including those located internally or in high-risk areas like near the eyes or airway. Topical propranolol, a gel or ointment, is used for smaller, superficial hemangiomas confined to the outer skin layer.
Initiating oral propranolol requires medical supervision, often beginning with a starting dose in a clinical setting for close monitoring of heart rate, blood pressure, and blood sugar. This ensures the infant tolerates the medication without issues. Dosing is based on the infant’s weight, starting at a low level and gradually increasing to a target dose that is divided and given multiple times a day.
Parents are instructed to give the oral syrup two or three times a day. The duration of treatment varies but often continues for several months through the infant’s first year to cover the hemangioma’s growth period. Regular follow-up appointments are scheduled to monitor the hemangioma’s response and adjust the dosage as the infant grows.
Potential Side Effects and Monitoring
While propranolol is considered safe, it can have side effects that require monitoring. Common reactions are often mild and manageable. These can include coolness in the hands and feet, minor digestive issues like diarrhea, and sleep disturbances such as restlessness or nightmares.
Less common but more serious side effects require immediate medical attention. These include a significant drop in heart rate (bradycardia), low blood pressure (hypotension), and difficulty breathing (bronchospasm). Another concern is hypoglycemia, or low blood sugar, which is why the medication should be given with feedings. Signs of hypoglycemia in an infant can include lethargy or a disinterest in their surroundings.
To manage these risks, a child may have an electrocardiogram (ECG) before starting to check their heart’s baseline function. Parents are educated on what to watch for at home, especially signs of low blood sugar or breathing issues. If an infant develops a cold or is not feeding well, doctors may advise temporarily stopping the medication to avoid complications.
Expected Outcomes and Efficacy
Propranolol treatment is highly effective, with most infants showing a positive response. Visible improvements often appear within the first few weeks. Parents first notice a change in the hemangioma’s color to a duller purple, followed by a softening in texture and a gradual reduction in size. Studies show that around 88% of infants improve within five weeks of treatment.
The goal of therapy is to stop the hemangioma’s growth and accelerate its shrinking process. Treatment continues for an average of six to twelve months. After the course is complete, many hemangiomas are significantly smaller and less noticeable. In some cases, there might be rebound growth after stopping the medication, which can be managed by restarting treatment.
While the medication can lead to nearly complete resolution, some residual skin changes may remain. These can include slight discoloration, textural differences, or tiny, dilated blood vessels (telangiectasias). For significant remaining cosmetic concerns, other treatments like laser therapy or surgery may be considered later. Propranolol helps prevent complications and reduces the need for more invasive procedures.