An allergy can be defined as a reaction of the body to an external agent which can not be recognized by its immune system. They may be caused due to some internal reactions caused by certain external agents.
In any case allergies occur when the immune system of an individual fails to fight a foreign particle and as a reaction to that failure.
Allergies unlike the diseases caused by microorganisms vary from individual to individual. Certain agents which cause an allergy in some individuals may not cause allergy in another individual. It entirely depends upon the immune system of a particular individual.
The symptoms of various allergies also vary according to the agents which cause them. Some allergies cause sneezing and coughing, some can cause vomiting while some cause skin rashes and etc.
Based on the allergen agents and the symptoms of the allergy, there are seven broad categories of allergies:
Food allergies are probably the most common type of allergies. These allergies are caused by certain food products.
The symptoms of food allergies are mostly vomiting, stomach ache, diarrhea and bloating. Certain food allergies may also cause rashes and acne on skin. In many cases food allergies can be very severe and even fatal.
Common food allergies are fish allergy, milk allergy, peanut allergy, wheat allergy and soy allergy. There are many other kinds of food allergies as well.
Types Of Rashes
The term rash does not refer to any particular disorder or a disease rather a rash is defined as an inflammation of skin followed by the appearance of red spots or marks on the skin causing severe itching.
Types Of Shock
In medical terms a shock is a condition in which various cells of the body fail to receive enough oxygen as there is an insufficient supply of blood to the entire body parts.
Different Types Of Acne
Acne is a common skin disease which is characterized by the appearance of pimples on skins. These pimples are formed when the hair follicles under the skin get clogged up with oil and dirt.
Drug allergies are probably the most dangerous kind of allergies.
They are caused by drugs such as penicillin, sulfa drugs, codeine and certain antibiotics and pain killers.
The symptoms of these allergies are mostly severe and include intense vomiting, fever and skin rashes.
In extreme severe conditions a drug allergy may also cause anaphylactic shock which can be fatal.
Hence it is very important that before taking a drug one must consult a specialist and get it checked.
Dust allergies are caused by dust particles and are very common.
When dust particles enter some individuals their body can not cope with it and an allergic reaction occurs as a result.
The symptoms of dust allergies include coughing and sneezing but in some individuals swelling may also occur.
Dust allergies are mostly minor; they can be irritating but are rarely dangerous. In very few cases they may cause serious reactions.
Mostly these allergies are put under the category of seasonal allergies, but in my opinion they deserve a separate spot.
These allergies are caused by pollens which are small dust like spores released by plants for the means of reproduction.
Since their concentration in the air is high during the spring, pollen allergies mostly occur during spring. This allergy is also very common and many individuals suffer from it.
The symptoms of pollen allergy are pretty much like dust allergies but a little more severe.
In many cases fever and swelling is accompanied by severe coughing and sneezing. The pollen allergies are also rarely dangerous.
Insect Bite And Animal Allergies
These allergies are also another common type of allergies which are caused by certain insect bites and fur of some animals.
Allergies caused by insect bite are not mostly variable and occur in almost ever individual if they are bitten by insects whereas animal allergies vary from individual to individual.
A bee sting for example causes swelling in every individual who gets it. Similarly a wasp sting also causes swelling and fever. Certain insect bites can be extremely dangerous.
Animal allergies are caused by the fur of some animals. People who are allergic to a certain animal may start coughing, sneezing or get swelling when in contact with that animal. Common animal allergies are cat allergy and dog allergy.
An allergy caused by any agent results in the formation of acne, rash and swelling on the skin is called skin allergy.
Skin allergies mostly occur due some food reaction, drug reaction or when body comes in contact with a certain metal.
Skin allergies may be minor or severe depending on the agent causing them. Most skin allergies are serious and are difficult to get rid of.
Seasonal allergies occur when weather suddenly changes or when it reaches on its extreme.
Most seasonal allergies result in severe flu and fever.