A dairy allergy occurs when the immune system reacts to the ingestion of milk proteins. Approximately 2.5 percent of infants and children younger than age 3 develop a milk allergy, reports the American Academy of Allergy, Asthma & Immunology.

Approximately 2 percent of adults and 6 percent of children have a food allergy, according to the FamilyDoctor.org website. Any food can trigger an allergic reaction, including a lemon. Symptoms of a lemon allergy can occur within minutes after contact with the fruit or can take up to two hours to manifest.

Nonoxynol-9 is a common ingredient found in all spermicide in the United States, according to the Mayo Clinic. Spermicides containing nonoxynol-9 can be used alone or with condoms, cervical caps and other contraceptive methods.

Both Zyrtec and Zyrtec-D are over-the-counter antihistamines that contain cetirizine. They function by reducing the chemical histamine in the body, which can cause symptoms of sneezing, itching, watery eyes and runny nose upon exposure to an allergen.

Although mold allergies can cause nasal congestion, nasal discharge, dry or scaly skin and sneezing, some individuals find the itching they experience from their mold allergy the most unpleasant or bothersome.

Corticosteroids are a type of steroid hormones that are produced in the adrenal cortex. When the adrenal cortex does not produce enough of these hormones, synthetic versions of the hormones may be administered to prevent unwanted symptoms.

Experiencing a headache and nausea after eating a meal can be frightening, particularly if it happens consistently. Any one of a number of underlying health issues could be to blame, particularly a food allergy or a food intolerance.

Tapioca flour, or tapioca starch, comes from the cassava plant. This gluten-free starch can help improve the flavor and texture of gluten-free baked goods. Gluten is responsible for building the structure of breads and other baked goods, giving these foods a characteristic chewy texture.

Sometimes the immune system perceives a threat and reacts in a variety of ways. A respiratory or lung allergy causes symptoms directly reflected in how a person breathes. Pollen, a major trigger for asthmatics, stimulates white blood cells to release a substance called histamine.

A sensitivity or allergy to petroleum can be a major problem because petroleum and its derivatives are present in many everyday products. Most petroleum-related allergies are respiratory in nature because the inhaled vapors are potent and even toxic to some people.

Food allergies occur when the immune system has a negative reaction to the proteins found in a certain food. MayoClinic.com states that 6 to 8 percent of children under age 5 have food allergies, as do 3 to 4 percent of adults.

A food allergy develops when the body has an abnormal response to a certain food or ingredient. In the case of white bread, the allergen is typically wheat. Because symptoms can be extreme and affect the quality of life, it’s important to understand why an allergy to white bread occurs and how you can treat it.