The immune system is designed to protect the body against harmful microorganisms, such as germs. Sometimes the immune system is experiencing chaos and attacking foreign substances which are harmless, causing losses instead of profits. This condition is called allergic (if the attack comes from outside the body, such as pollen or bee sting) and is called autoimmune (if it attacks the body's own components).
Immune system usually only respond to certain chemical substances, called proteins. But the non-protein substances can also trigger the same response. Allergic skin reactions do not occur when triggered by a protein.
Several factors that often cause skin allergies, among others:
- Minor injuries (eg scratching) causes a small bump-bump itching (urticaria), presence of urticaria is a condition called with dermografisme.
- Cold can change certain proteins in the blood resulting in an immune reaction. This could indicate that the abnormal protein in the blood derived from bone marrow disorders.
- Allergy to the heat can be caused by exercise or even by strong emotions (on the people who are sensitive).
- Sunlight (even without drugs) causing the urticaria, this situation could be a symptom of porfiria (a disorder of metabolism that are derived).
- Elements (such as nickel and chromium), although not a protein, often causing skin rashes, allergies iodine can cause skin rashes and sores in the mouth.
- Pressure or vibration can also cause urticaria.
- Contact with water can cause urticaria akuagenik, possibly because of the chlorine or other minerals in the water.
- If the inflammatory reaction involves deeper layers of the skin condition called angioedema. Skin, especially skin swollen lips and eyelids, this can also involve the tongue, throat and digestive tract part.
- Angioedema can be caused by physical agents, but the cause is often unknown.
- Skin allergy symptoms that are often found is itchy, spots on the skin. Strong reaction to sunlight (photosensitivity) can cause skin spots that are not regular. Someone very sensitive to heat may experience cholinergic urticaria, characterized by small stripes surrounded by a ring of red and feeling very itchy. Cholinergic urticaria also may result from exercise, emotional stress or a variety of activities that cause sweating.
- People who are sensitive to cold, if exposed to cold weather can have spots on the skin, and swelling of the skin.