Allergic reactions are due to an abnormal immune reaction to a harmless foreign substance. Allergies may take a variety of forms, from bronchial asthma, to hives, to severe anaphylactic reactions. Glucocorticoids are a type of steroid that suppresses inflammation and are commonly used drugs in the treatment of allergies. Although they are remarkably effective, they have a number of side effects and should be used only when necessary.
Suppressing Allergic Reactions
Glucocorticoids have a number of suppressing effects on the immune system. They reduce the activity of lymphocytes, cells which are responsible for stimulating inflammatory cells and which produce antibodies that can trigger allergies. In addition, they have been shown to block the activities of basophils, cells that produce histamine. Because allergies are due to abnormal immune activation, these steroids are useful medications to suppress this response.
Skin Allergies
Skin allergies can occur in a variety of forms. A skin reaction like hives can occur due to food allergies, bee stings, pollen allergies or the consumption of certain medications. It often takes the form of itchy, red welts on the skin. You can treat hives by avoiding the substance that triggers the reaction. Oral steroids are effective in treating cases of hives.
A different kind of skin allergy is known as contact dermatitis. This rash can occur following exposure to poison ivy, oak and sumac. It also frequently occurs in people with nickel allergies when they wear certain kinds of jewelry. The rash occurs one to two days after exposure to the irritating substance and appears as a red, itchy rash. Steroid creams containing hydrocortisone are useful in resolving these allergies.
Asthma
Asthma is a condition characterized by episodic breathlessness and wheezing. While mild asthmatics, in whom symptoms occur less than twice a month, can be treated with an albuterol inhaler, people with more frequent symptoms should use a steroid inhaler. Commonly used glucocorticoids are fluticasone and beclomesthasone. Taking an inhaled steroid on a regular basis reduces the frequency and severity of asthma episodes. Inhaled steroids have very few side effects and can be taken for prolonged periods of time. Sometimes patients with asthma may have very severe symptoms that need emergency room treatment; in these patients an oral or injected steroid is useful to help reduce the symptoms.
Allergic Rhinitis
Nasal allergies are common in the springtime and are often due to pollen. This manifestation is often called "hay fever." Common symptoms include sneezing, a watery nasal discharge and nasal obstruction. The first line treatment for these conditions is antihistamines. Patients with persisting symptoms can be treated with a steroid nasal spray. Commonly used steroids are beclometasone and budesonide.
Dangers of Glucocorticoids
While glucocorticoids are very effective for a variety of allergic disorders, doctors try to minimize their use. These steroids have a variety of side effects. They can cause weight gain, osteoporosis and increased susceptibility to infections. Patients taking steroids should take the smallest dose possible and for the shortest duration of time.
References
- PubMed Health: Hives
- PubMed Health: Contact Dermatitis
- "Davidson's Principles and Practice of Medicine"; Nicki R. Colledge, et al.; 2010
- "Rang & Dale's Pharmacology"; Humphrey P. Rang, et al.; 2007
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