DSM-IV & DSM-IV-TR:

Specific Phobia

Diagnostic criteria for 300.29 Specific Phobia  
(cautionary statement)  

A. Marked and persistent fear that is excessive or unreasonable, cued by the presence or anticipation of a specific object or situation (e.g., flying, heights, animals, receiving an injection, seeing blood). 

B. Exposure to the phobic stimulus almost invariably provokes an immediate anxiety response, which may take the form of a situationally bound or situationally predisposed Panic Attack. 
Note: In children, the anxiety may be expressed by crying, tantrums, freezing, or clinging. 

C. The person recognizes that the fear is excessive or unreasonable. Note: In children, this feature may be absent. 

D. The phobic situation(s) is avoided or else is endured with intense anxiety or distress. 

E. The avoidance, anxious anticipation, or distress in the feared situation(s) interferes significantly with the person's normal routine, occupational (or academic) functioning, or social activities or relationships, or there is marked distress about having the phobia. 

F. In individuals under age 18 years, the duration is at least 6 months. 

G. The anxiety, Panic Attacks, or phobic avoidance associated with the specific object or situation are not better accounted for by another mental disorder, such as Obsessive-Compulsive Disorder (e.g., fear of dirt in someone with an obsession about contamination), Posttraumatic Stress Disorder (e.g., avoidance of stimuli associated with a severe stressor), Separation Anxiety Disorder (e.g., avoidance of school), Social Phobia (e.g., avoidance of social situations because of fear of embarrassment), Panic Disorder with Agoraphobia, or Agoraphobia Without History of Panic Disorder. 

Specify type:
Animal Type 
Natural Environment Type (e.g., heights, storms, water) 
Blood-Injection-Injury Type 
Situational Type (e.g., airplanes, elevators, enclosed places) 
Other Type (e.g., phobic avoidance of situations that may lead to choking, vomiting, or contracting an illness; in children, avoidance of loud sounds or costumed characters)