Dysregulation of the HPA axis has been associated with eating disorders, such as irregularities in the manufacture, amount or transmission of certain neurotransmitters, hormones or neuropeptides and amino acids such as homocysteine, elevated levels of which are found in AN and BN as well as depression.Serotonin: a neurotransmitter involved in depression also has an inhibitory effect on eating behavior. Norepinephrine is both a neurotransmitter and a hormone; abnormalities in either capacity may affect eating behavior. Dopamine: which in addition to being a precursor of norepinephrine and epinephrine is also a neurotransmitter which regulates the rewarding property of food. Neuropeptide Y also known as NPY is a hormone that encourages eating and decreases metabolic rate. Blood levels of NPY are elevated in patients with anorexia nervosa, and studies have shown that injection of this hormone into the brain of rats with restricted food intake increases their time spent running on a wheel. Normally the hormone stimulates eating in healthy patients, but under conditions of starvation it increases their activity rate, probably to increase the chance of finding food. The increased levels of NPY in the blood of patients with eating disorders can in some ways explain the instances of extreme over-exercising found in most anorexia nervosa patients. Leptin and ghrelin: leptin is a hormone produced primarily by the fat cells in the body; it has an inhibitory effect on appetite by inducing a feeling of satiety. Ghrelin is an appetite inducing hormone produced in the stomach and the upper portion of the small intestine.
Signs in phlyctenular keratoconjunctivitis include small yellow nodules that develop over the cornea, which ulcerate after a few days.A study by Klein et al. showed that in addition to the physical discomfort allergic conjunctivitis causes, it also alters patients routines, with patients limiting certain activities such as going outdoors, reading, sleeping, and driving. Therefore, treating patients with allergic conjunctivitis may improve their everyday quality of life. Causes
The cause of allergic conjunctivitis is an allergic reaction of the bodys immune system to an allergen. Allergic conjunctivitis is common in people who have other signs of allergic disease such as hay fever, asthma and eczema.Among the most common allergens that cause conjunctivitis are:
Pollen from trees, grass and ragweed
Animal skin and secretions such as saliva
Perfumes
Cosmetics
Skin medicines
Air pollution
Smoke
Dust mites
Balsam of Peru (used in food and drink for flavoring, in perfumes and toiletries for fragrance, and in medicine and pharmaceutical items for healing properties)
Eye drops (A reaction to preservatives in eye drops can cause toxic conjunctivitis)
Contact lens solution (some preservatives can irritate the eye over time resulting in conjunctivitis)
Contact lens (conjunctivitis is also caused by repeated mechanical irritation of the conjunctiva by contact lens wearers)Most cases of seasonal conjunctivitis are due to pollen and occur in the hay fever season, grass pollens in early summer and various other pollens and moulds may cause symptoms later in the summer. Pathophysiology
The ocular allergic response is a cascade of events that is coordinated by mast cells.