Special Report

16 Symptoms You May Not Know Are Allergic Reactions

Source: SolStock / Getty Images

Earache

Earaches are most commonly caused by ear infections, but seasonal allergies may also be the underlying cause. When the body reacts to pollen or other allergens as if they were a harmful substance, the immune system releases histamines, which may cause the mucous membranes in the nasal cavities and ears to become inflamed. The inflammation may prevent fluid or mucus from draining away, and that congestion may cause the earache.

Source: AntonioGuillem / Getty Images

Asthma attacks

The same allergens that cause watery eyes in some people may cause an asthma attack in others. The body identifies what is actually a harmless substance like tree pollen or grass as harmful bacteria. To protect itself, the immune system releases histamines, which leads to allergy symptoms. In some people, however, the histamine also affects the lungs and airways, leading to asthma symptoms.

Source: PeopleImages / Getty Images

Frequent infections

Infections are not a common sign of allergies, but they are possible, especially in people already with immune deficiencies. Allergies can lead to congestion, which in turn can lead to fluid buildup in the sinuses, increasing the risk of infection in the ears and sinuses.

Source: Boyloso / Getty Images

Dark circles under the eyes

Dark circles under the eyes are usually caused by extreme fatigue or chronic sleep deprivation. They may be a symptom of allergies as well. The condition is called allergic shiners. Allergens cause inflammation that expands the tiny blood vessels under the eyes. The congestion of small blood vessels beneath the thin skin of the eyes causes a dark color to appear.

Source: RuslanDashinsky / Getty Images

Loss of sense of smell

Allergens that irritate the nose’s lining may lead to temporary anosmia — the complete loss of sense of smell. This is not a very common symptom of hay fever, unless the allergies are severe. What also may cause anosmia is a cold, sinus infections, or poor air quality.