Histamine is the chemical/hormone in the body that causes allergic reactions. According to FamilyDoctor.org, when someone encounters an allergen, the body releases IgE antibodies to fight off the substance. This release causes a chain reaction in the body that causes the mast cells to over-produce histamine. Increased histamine causes irritation and inflammation in various parts of the body. The most common places histamine causes a reaction is in the skin, the nasal passages and the bronchial tubes. Talk with a doctor about any allergy-related symptoms for the most effective treatment options.
Upper-Respiratory Symptoms
The most common condition in the upper-respiratory system affected by histamine release is called allergic rhinitis. This allergy condition primarily focuses on the sinuses and the eye's reaction to increased histamine, according to the University of Maryland's Medical Center. Common symptoms include nasal congestion, a runny nose, sneezing and sinus pressure pain. Post nasal drip is associated with allergic rhinitis, especially when the nostrils are obstructed. Other symptoms in the upper-respiratory tract are irritation in the eyes and throat irritation. The eyes become red, swollen, watery and very itchy. The throat feels scratchy and can become sore from post nasal drip.
Skin Symptoms
The release of histamine can cause skin rashes throughout the body, according to the American Academy of Dermatology. This type of reaction causes symptoms such as redness, inflammation and severe itching on the skin. The skin can develop welts or small blisters that can burst, making the skin more susceptible to infections, such as impetigo. The most common skin reactions caused by increased histamine levels are eczema, hives and contact dermatitis. Avoid scratching the skin, wear loose fitting clothing, and stay away from hot and humid conditions. Talk with a doctor if skin symptoms do not improve within a 24-hour period.
Asthmatic Symptoms
Asthmatic symptoms due to the release of histamine are referred to as allergy-induced asthma, according to the Asthma and Allergy Foundation of America. Allergy-induced accounts for 50 percent of asthma condition in the United States. When the body releases histamine, it causes the bronchial tubes to become inflamed and swollen. This leads to restricted breathing and wheezing. The person may feel tightness in the chest and will not be able to take a deep breathe. She may feel faint or develop anxiety because of the lack of air. Asthma can lead to a life-threatening situation and needs to be evaluated by a physician.
