<unk>  (Greek ατοπία - placelessness) or<unk> c syndrome is an allergic hypersensitivity affecting parts of the body not in direct contact with the allergen. It may involve eczema <unk> c dermatitis), allergic conjunctivitis, allergic rhinitis and asthma. There appears to be a strong hereditary component. One study concludes that "the general risk of developing<unk> c dermatitis (3%) and<unk>  (7%) increases by a factor of two with each first-degree family member already suffering from<unk> "
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The hereditary component is presumably due to certain genes coding proteins involved in the normal immune response mechanism, i.e., human leukocyte antigen, although environmental factors have also been implicated.<unk> c syndrome can be fatal for those who experience serious allergic reactions such as anaphylaxis, brought on by reactions to food or environment.
The individual components are all caused at least in part by allergy (type I hypersensitivity reactions). These responses appear after the body is exposed to various allergens, for example specific kinds of food, pollen, dander or insect venoms. Although<unk>  has various definitions, most consistently it is defined by the presence of elevated levels of total and allergen-specific IgE in the serum of patient, leading to positive skin-prick tests to common allergens.
The multicenter PARSIFAL study in 2006, involving 6630 children age 5 to 13 in 5 European countries, suggested that restrictive use of antibiotics and antipyretics, are associated with a reduced risk of allergic disease in children.
Some symptoms, from an<unk>  questionnaire:
Cracks in the skin under the earlobe
Eczema
In elbow flexures and/or hollow of the knees
Nipple eczema
Neurodermatitis
Subtype Dyshidrosis
Keratosis pilaris
Perlèche
Conjunctivitis
Chronic or seasonal rhinitis
In elbow flexures and/or hollow of the knees
Nipple eczema
Neurodermatitis
Subtype Dyshidrosis
Atopy
Wide complex tachycardia
Junctional rhythm
Supraventricular arrhythmias
Junctional tachycardia
Narrow complex tachycardia
Junctional bradycardia
Long PR interval