Which are the causes of Eosinophilic esophagitis?

Eosinophilic Gastrointestinal Disorder (EGID) is a complicated digestive system disorder in which eosinophils, a type of white blood cell, are found in above-normal amounts in one or more specific places in the digestive system and/or the blood.
When the body wants to attack a substance, such as an allergy-triggering food or airborne allergen, eosinophils respond by moving into the area and releasing a variety of toxins. However, when the body produces too many eosinophils, they can cause chronic inflammation, resulting in tissue damage.
These rare diseases are diagnosed according to where the elevated levels of eosinophils are found:
Eosinophilic esophagitis (esophagus)
Eosinophilic gastritis (stomach)
Eosinophilic enteritis (small intestine)
Eosinophilic colitis (large intestine)
Hypereosinophilic syndrome (blood and any organ)
Eosinophilic Disorder can be divided into two types, Primary and Secondary. The Primary type is further subdivided into allergic and non-allergic forms. The allergic type occurs in association with food allergies, while the non-allergic form occurs when no obvious cause can be found to explain the high number of eosinophils in the digestive system. Because of this, the non-allergic form is thought to be evidence that the body is attacking itself and considered to be an autoimmune disorder.
Symptoms
Common symptoms may include pain, swelling, skin rash, hives can occur, reflux, choking, difficulty swallowing, nausea, vomiting, loss of appetite, stools containing blood and/or mucus, abdominal cramping, diarrhea, fever, esophageal rings, motility problems, bowel obstruction, bowel or stomach wall thickening (from scar tissue buildup), pseudopolyps, protein loss, anemia, malabsorption, developmental delay, bleeding, and several other symptoms that occur in individual cases. Many people also experience nutritional deficiencies and/or side effects from medications, such as neuropathy (nerve damage) or osteoporosis (decrease in bone mass).
Treatment Options
Special amino acid-based formula may be needed as a supplement for those whose diets are so limited that they are unable to obtain enough nutrition from food alone. Some primary forms may require the avoidance of all regular foods and complete reliance on an amino acid-based formula, which maybe consumed normally or pumped through a special feeding tube (naso-gastric, gastrostomy or jejunostomy tubes).
For the most severe flare-ups or for those who experience problems from all foods and formulas, feeding through a blood vessel (TPN) may be the only remaining option. Some cases also require additional symptom-specific help, such as pain medication. This disease may cause such severe bleeding or nutritional deficiency that they condition may be life threatening if not treated with appropriate medications.
Since there is no known cure for Eosinophilic Gastrointestinal Disorder, management of the condition is very important in order to prevent severe damage to the digestive system (and to the organs in the case of Hypereosinophilic syndrome) caused by the high numbers of eosinophils. Because symptoms vary so widely and may mimic other conditions, it is important that accurate information and awareness of Eosinophilic Gastrointestinal Disorder is achieved.