An allergic reaction occurs when your body’s immune system reacts abnormally to things that are normally harmless. Signs of an allergic reaction can vary greatly depending on the individual and the type of allergy. Babies are much less likely than older children and adults to have many types of allergies, because you must be exposed to some things for a time before becoming allergic to them. Seasonal allergies, for example, are uncommon in babies as they haven’t lived through a season or two of high pollen counts. Most types of inhaled allergies are uncommon before 1–2 years old.
Food and medicine allergies
Symptoms of a food or medicine allergy may appear within a few minutes, or an hour or two later. Some drug allergy signs, such as rashes, may not appear for several days. The most common signs of food and medicine allergies include:
- hives or rashes
- itching
- wheezing or shortness of breath
Food allergies can also result in nausea, vomiting, or abdominal pain. In some cases, your baby’s lips or tongue may start to swell. A potentially fatal reaction to a serious food or medicine allergy is a condition called
anaphylaxis. It occurs when exposure to an allergen triggers overproduction of certain body chemicals. Those chemicals can send you into shock. Blood pressure will also drop dramatically and the airways narrow, making breathing difficult. For children, severe food allergies are the
most common reasons for anaphylaxis, but in rare cases, medications such as antibiotics and
aspirin can be responsible. Bee stings and other insect stings or bites can also cause anaphylaxis. Anaphylaxis is rare in babies and is almost always due to cow’s milk protein allergy.
Environmental allergies
Though uncommon in babies, allergies to dust, pets, mold, pollen, insect stings, and other things in the environment may trigger allergy symptoms that affect the head and chest, such as:
- sneezing
- red and itchy eyes
- coughing, wheezing, and chest tightness
- runny nose
Your baby may also develop hives, a rash, or itchy bumps if their skin is exposed to an allergen or something to which they are sensitive. Shampoos, soaps, detergents, and similar products are common triggers for a reaction called
contact dermatitis.
Seasonal allergies
The main symptoms of seasonal allergies, which are usually caused by plant-based allergens, are similar to environmental allergy symptoms, and may include:
- sneezing
- itchy or watery eyes
- coughing
- runny nose
If your baby has these symptoms only at certain times of the year, they may have seasonal allergies.