Symptoms, Causes, Treatment, and More

You may expect the signs of asthma to be obvious in infants—classic sudden attacks of wheezing, coughing, and shortness of breath. But they often can be subtle and easily mistaken for a respiratory infection. Because of this, and the fact that little ones can’t describe how they are feeling, many parents have no idea their infant has asthma until the attacks are more severe or overt.

Knowing how to differentiate infant asthma from common respiratory illnesses is one key to getting early diagnosis and treatment. Doing so will improve your baby’s quality of life as well as prevent lung injury that can persist into later years.

Types of Infant Asthma

There are many different types of asthma, each with different triggers and outcomes. From a broad perspective, asthma can be classified as either:

• Allergic asthma, also known as atopic or extrinsic asthma, which is triggered by allergens such as pollen and certain foods
• Non-allergic asthma, also known as non-atopic or extrinsic asthma, in which symptoms develop in the absence of allergy

The distinction is especially important in infants, the vast majority of whom will develop allergic asthma. As an atopic disorder (meaning one with a genetic tendency toward allergy), allergic asthma is often part of a progression of disorders referred to as the “atopic march.”

The atopic march classically begins with the development of atopic dermatitis (eczema), often in the first six months of life. This initial atopy triggers changes in an immature immune system that opens the door to food allergies, which in turn opens the door to allergic rhinitis (hay fever) and, finally, asthma.

The progression can either happen slowly over the course of years or rapidly during the first months of life.

The severity of asthma is also closely linked to a child’s history of eczema. If there is mild eczema during infancy, the symptoms of asthma will also tend to be mild and may resolve fully by puberty. On the other hand, if the eczema is severe, the asthma symptoms will generally be severe and may persist into adulthood.

It’s important, to remember, however, that not every infant with eczema will develop asthma, and not every infant with asthma will have had eczema. Asthma is a complex disease for which many factors contribute to both the onset and severity of symptoms.

Infant Asthma Symptoms

The symptoms of asthma in children and adults are more or less the same but can vary from person to person in terms of severity and frequency.

Even so, there are characteristic differences in asthma symptoms in infants (under 1 year) and babies (between 1 and 4) compared to toddlers and young children (4 to 11). This is due, in part, to differences in airway sizes as well as the overall strength and capacity of the lungs.

Signs of an Emergency

Call 911 or seek emergency care if your child experiences signs of a severe attack, including: 

• Wheezing while breathing both in and out
• Coughing that has become continuous
• Rapid breathing with retraction
• Sudden paleness
• Blue lips or fingernails
• Inability to eat, talk, or play (as is age appropriate)
• Abdominal contractions while breathing

Complications

Infant asthma may spontaneously resolve by puberty in some children, but early treatment is vital to preventing injury in still-developing lungs. Ongoing inflammation spurred by untreated asthma can lead to airway remodeling, a common occurrence in older children with asthma.

When this occurs, the smooth muscles of the airways begin to thicken and lose their flexibility, while the goblet cells that produce mucus will grow in size. This can increase the risk of chronic obstructive pulmonary disease (COPD) later in life.

Causes

According to the Centers for Disease Control and Prevention (CDC), more than six million children in the United States have asthma, most of whom develop symptoms before age 6.

It is unknown what causes asthma in children and adults. The current evidence suggests a genetic predisposition paired with environmental factors alters the body’s immune response, increasing airway hyperresponsiveness to environmental and physiologic triggers.

As far as infants are concerned, there is evidence certain factors can increase a child’s risk of developing asthma.

• A family history of asthma is the major risk factor for allergic asthma, more than tripling a child’s risk if another sibling has asthma.
• Not breastfeeding may deprive babies of maternal antibodies that help build a robust immune system. (The American Academy of Pediatrics recommends infants exclusively receive breastmilk for around the first six months of life, at which time solid foods may be added in as a complement. )
• Household dampness and mold can cause an immature immune system to produce defensive antibodies to mold spores in the air, increasing the risk of allergies and allergic asthma.
• Being born in early autumn more than doubles a child’s risk of allergic asthma by exposing their immature immune system to wind-borne pollen and mold.
• Secondhand smoke exposes a baby’s lungs to inflammatory toxins that may increase the risk of airway hyperresponsiveness.
• Severe respiratory infections before age 2, especially lower respiratory tract infections, may promote changes in airway tissues that can lead to hyperresponsiveness.
• Nutrition may also play a role in the development of allergic asthma by preventing egg and milk allergies. The risk of a milk allergy may be reduced with breastfeeding, while feeding babies eggs may reduce the risk of egg allergies.

Diagnosis

Diagnosing asthma in infants and babies is difficult because the central tools used for diagnosis—pulmonary function tests (PFTs)—do not return useful results in most cases. Even a simple exhaled nitric oxide test, which measures the amount of the gas present when one breathes out, is of little use in children under 5.

To this end, doctors rely heavily on an infant’s symptoms, a parent or guardian’s observations, and other information to make an asthma diagnosis. The process involves an extensive interview to assess the child’s history of breathing problems.

Questions may include:

• Does anyone in the family have asthma? A family history of eczema or allergic rhinitis is also predictive of asthma.
• How often does your child experience wheezing? Although wheezing is common in many childhood illnesses, asthma is characterized by recurrence—often for no apparent reason.
• When does your child experience wheezing? Some caretakers may recall events or patterns that precede the attacks, like being outdoors, being near pets, or drinking milk. Triggers like these may support the diagnosis.
• What does the wheezing sound like? In some cases, the sound of wheezing can help differentiate causes. A barking sound, for example, is common with pertussis (whooping cough), while “chesty” wheezing with a mucusy cough is more indicative of a bronchial infection. With asthma, the wheezing will be high-pitched with a dry cough.
• Does your child cough at night? Nighttime cough and wheezing are among the defining features of asthma in children.
• Does your child have trouble feeding? Oftentimes, an infant with asthma will not be able to finish a bottle due to the shortness of breath.
• Does your child wheeze after laughing or crying? Heavy laughter or crying can trigger an attack by causing hyperventilation and bronchial spasms.

Examination and Testing

The doctor will also perform a physical exam to check for breathing sounds (some of which may suggest an infection or airway obstruction) or atopic skin conditions like eczema.

If a cause is not readily found, a chest X-ray may be ordered; this common imaging study is safe for newborns and infants. However, it is better at excluding other causes of wheezing and shortness of breath than confirming asthma.

If allergic asthma is suspected, the doctor may recommend allergy skin testing involving the insertion of tiny amounts of common allergens (such as pet dander) under the skin to see if a reaction occurs. Even so, allergy skin testing is rarely performed in children under 6 months old.

Differential Diagnoses

Other tests may be ordered, including blood tests and imaging studies, to exclude other causes of your baby’s symptoms. Among the conditions commonly included in the differential diagnosis of infant asthma are:

Treatment

If asthma is diagnosed in a child under 2 and their symptoms are mild, a doctor may take a wait-and-see approach. This is partly because there’s been little research into the safety of asthma drugs for children this young.

If treatment is needed, many of the same medications used for adults can be considered. The selection would be based on the risk of side effects, the frequency and severity of attacks, the impact of asthma on the child’s quality of life, and whether the drug is approved for use in children.

Among the treatments available to children under 4:

• Rescue inhalers, used to treat acute attacks, are approved for children 2 and over, although minimal use is recommended. The only exception is Xopenex (levalbuterol), which is approved only for children 6 and over.
• An inhaled corticosteroid (ICS) may be used for several days or weeks to gain control of asthma symptoms. Pulmicort (budesonide) delivered via nebulizer is the only inhaled corticosteroid approved for children 1 and older. Other options are approved only for children 4 and over.
• Singulair (montelukast), a leukotriene modifier, also may be considered if inhaled corticosteroids fail to provide relief. The drug is available in granulated form for children 1 and older.
• Theophylline, an older and less commonly used oral drug, can be added to the treatment plan for children 1 and over if needed.

There are no FDA-approved asthma medications for children under 1, but the Global Initiative for Asthma (GINA) recommends nebulized albuterol (a rescue medication) every 20 minutes for the first hour to treat acute symptoms in infants.

Among the additional treatments available to children over 4:

• Cromolyn sodium, a mast cell stabilizer delivered by nebulization, may be considered if inhaled corticosteroids fail to provide relief. The drug is contraindicated for children under 2.
• Salmeterol, a long-acting beta-agonist (LABA) used daily to control asthma, is reserved for children 4 and older. Other LABAs can only be used in children over 5 or 6.
• Oral and nasal spray antihistamines may be used to treat allergy symptoms in children with allergic asthma but are generally avoided in children under 4.
• Immunomodulator drugs, which temper the immune response in people with moderate to severe asthma, are avoided in babies and toddlers. The only option available for children 6 and over is Xolair (omalizumab).

Coping

If your infant or baby has been diagnosed with asthma, there are things you can do to reduce the risk of attacks and improve their quality of life:

• Follow the treatment plan: If medications are prescribed, understand how they are used, and use them only as prescribed. Do not experiment with treatment or change dosages without first speaking with your child’s doctor.
• Identify asthma triggers: By doing so, you can take steps to remove them from your home. If you don’t know what the triggers are, keep a symptom diary tracking events, food, activities, and symptoms as they occur. Over time, patterns may emerge that can help pinpoint symptoms.
• Use an air purifier: If seasonal allergies, pet dander, or dust are problematic for your child, find an air purifier with a multi-filter system (combining a HEPA filter with an activated charcoal filter). Check that the unit is able to service the size of the room in cubic feet.
• Keep smokers away from your child: If someone in the family smokes, have them do it outdoors. Or better yet, have them speak to their health provider about smoking cessation aids to help them quit.
• Have an action plan: Write down instructions on how to treat acute symptoms. Make sure everyone in the family, as well as any other caretakers, has a copy and is familiar with what to do. Be sure to include a doctor’s number and instructions on when to call 911 (including a clear description of the emergency signs and symptoms).

Summary

Diagnosing asthma in infants can be difficult even for medical professionals, as many diagnostic tests are not accurate for children under 5 and asthma is often mistaken for other common respiratory illnesses. It is important, though, to treat asthma (which is often linked to eczema and allergies) early in order to prevent ongoing injury to still-developing lungs.

Caregivers should know what symptoms to look for in an infant and they should promptly relay these symptoms to a pediatrician and/or pediatric pulmonologist. Many of these are similar to characteristic signs of asthma—like wheezing and coughing—in older children. Infants might also experience nasal flaring and retraction of the muscles between the ribs while breathing—which are signs that emergency medical attention is needed.