A phobia is an exclusive sense of fear from a strong, uncontrollable and zany feeling. It brings about nervousness, restlessness and concern about a particular situation or event that is to occur or likely to occur.
Phobias are anxiety malfunctions whereby the malfunctions might not be experienced until when in contact with the source of the phobia.
Having thoughts about the source of a phobia can bring about anxiety and overpowering fright.
Most phobias occur for unexplained reasons while some are hereditary.
Symptoms of phobia may include; sweating, migraine, palpitations, shock, nausea, instability and dizziness.
Starting from the most feared to the least, here are the ten most common phobias around the world;
1. Arachnophobia
Arachnophobia is one of the oldest and the most common phobia, gotten from the word “arac
hnids” and “phobia”. It means the intense and irrational fear of joint legged invertebrate animals such as scorpions, spiders, ticks, mites etc. For example the presence of poisonous spiders will make the fear of spiders easy.
Although, many arachnids are not dangerous but someone with arachnophobia may still feel uncomfortable around one. Sometimes, a resemblance of a spider by an object can create panic in such individual.
2. Ophidiophobia
The word comes from “phobia” and the Greek word “ophis”(serpent). Ophidiophobia means the excessive fear of snakes,it is the second most common phobia. 
Someone with Ophidiophobia may find it difficult to visit where snakes are kept such as the zoo and where snake populations are high. Thoughts and anticipation of a snake by a person suffering from Ophidiophobia brings about intense fear and shock in such person.
3.Acrophobia
The word comes from “phobia” and the Greek word “acron”. Acrophobia means the excessive fear of falling and getting injured from great heights, people without acrophobia are said to have a head for heights which is advantageous in hiking and climbing mountains.
One of the major causes of acrophobia is having negative thoughts about falling.
People suffering from acrophobia experiences shock in high places, make loud noises and become too eager to get to safety.
4. Agoraphobia
Agoraphobia is from the word “phobia”and the Greek word “agora” .Agoraphobia m
Agoraphobia involves the fear of crowds or being outside alone where an escape may be difficult.
5. Cynophobia
Cynophobia is from the word “phobia” and the Greek word “kyon”. Cynophobia is the irrational fear of dogs and it is said to usually begin in early childhood.
When someone suffering from cynophobia comes in contact with dogs, thinks about or when presented with images whether still or filmed images of dogs an immediate anxiety response is said to occur.
People suffering from cynophobia may exhibit total avoidance behavior such as staying away from areas where dogs might be or avoiding homes of people who own dogs.
6. Astraphobia
Astraphobia is from the Greek word “astrape” and “phobia” meaning the intense fear of thunder and lightning. It is also known as tonitrophobia, brontophobia or nicaduranaphobia.
Astraphobia is an excessive fear of thunderstorms which causes people sufferin
The major cause of astraphobia in people is a serious injury related to thunder and lightning which might have even happened to a loved one.
Astraphobia can be treated with a series of therapies and drugs.
7. Claustrophobia
Claustrophobia is the excessive and irrational fear of enclosed, small or tight places such as crowded elevators and restricted places.
Claustrophobia is an anxiety malfunction that comes with fear of suffocation and fear of restriction. Fear of suffocation occurs when claustrophobics (people suffering from claustrophobia) think that there may be insufficient air when in enclosed or tight places while fear of restriction is the fear of being limited to a single place.
Claustrophobics can experience nausea, instability, palpitations or intense sweating when confined to an area.
8. Mysophobia
Mysophobia is from the Greek word “myso” and “phobia” meaning the excessive fear of dirt and germs or other microorganisms such as bacteria that can cause diseases. Mysophobia is also called verminophobia, bacillophobia, bacteriophobia and germaphobia.
People with the fear of germs and dirt believe exposure to dirt and germs is harmful and life-threatening therefore they tend to avoid contact with people especially those who are not hygienic, wash their hands repeatedly when they believe they are impure, not sharing personal belongings, utensils and even food.
9. Aerophobia
Travelling by air is the fastest and safest means of transportation and it causes fear in some people. The excessive or irrational fear of travelling by air is called Aerophobia, Aviophobia or Aviatophobia which comes from the Greek word “aero” and “phobia”.
Aerophobia occurs when a person thinks of flying or is about to fly whether in helicopters, planes or other flying vehicles and it brings about panic, trembling, increased heartbeat, shock, dry mouth and sweating.
Aerophobia can stand on its own or be a combination of one or more phobias such as acrophobia (fear of heights) or claustrophobia (fear of being confined to an area).
Aerophobia can be caused by the fear of having a crash which is likely to be fatal, the feeling of not being in control or the fear of being hijacked or subjected under terrorism which can be reduced by creating means of awareness of safety to individuals suffering from aerophobia.
10. Trypophobia
Trypophobia is an excessive or irrational fear of clustered holes or bumps especially tiny holes. It brings about sudden heart racing, severe headaches, chest pain, thoughts of death or dizziness. 
The objects causing trypophobia may include holes in living organisms, honeycombs, holes created by worms and ants or natural occurring geographical holes.