From MayoClinic.com 

Phobias are among several anxiety disorders, which also include panic disorder, post-traumatic stress disorder, obsessive-compulsive disorder and generalized anxiety disorder.

You may have a phobia. A phobia is a persistent irrational fear of an object or a situation. Accompanying the fear is a strong desire to avoid what you fear and, in some cases, an inability to function at normal tasks in your job and in social settings.

Treatment may help you reduce your fears and help you better manage the object or situation that makes you anxious.

• Anxiety

Signs and symptoms

Common phobias include:

• Simple phobias. These include a fear of: enclosed spaces (claustrophobia); animals, particularly spiders, snakes or mice; heights (acrophobia); flying (pterygophobia); water (hydrophobia); storms; dentists (odontiatophobia); tunnels; bridges; not being able to get off public transportation quickly. There are many other simple phobias.

• Social phobia. This involves a combination of excessive self-consciousness, a fear of public scrutiny or humiliation in common social situations, and a fear of negative evaluation by others.

• Fear of public places (agoraphobia). At least half the people with panic disorder develop agoraphobia, which is a fear of being alone in a place such as a mall or an elevator or a room full of people, and of there being no easy escape.

Having a phobia may produce the following signs and symptoms:

• Persistent, irrational fear of a specific object, activity or situation

• Immediate response of anxiety when exposed to the object of fear, even if it's just thinking about the object or seeing a picture of it

• Compelling desire to avoid what you fear

• Impaired ability to function at normal tasks because of the fear

In phobias, these signs and symptoms aren't due to another medical or psychiatric illness or to substance abuse.

When you face the object of your phobia, you may experience panicky feelings, such as sweating, rapid heartbeat, avoidance behavior, difficulty breathing and intense anxiety. In some cases, you may have anxious feelings not only when facing the object of your phobia, but also when merely anticipating an encounter with what you fear.

• Anxiety

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