CHAPTER XXVIII 

 I-IYPERSENSITIVENESS 



Human Idiosyncrasies 



Clinical Allergies. — It is generally recognized, at the present 

 time, that a large nnmber of individuals (variously estimated at 

 from 7 to 15 per cent) are abnormally sensitive to one or more 

 protein or nonprotein substances. In the group of clinical al- 

 lergies one places hay fever, asthma, urticaria, eczema, contact 

 dermatitis, serum disease and drug allergy. Rackemann and 

 others suggest that migraine, angioneurotic edema, erythema 

 multiforme and perhaps epilepsy are manifestations of hyper- 

 sensitiveness. 



Reactions Occur in Local Shock Organs. — In human idio- 

 syncrasies the reactions tend to be local rather than general. This 

 has led Doerr to introduce the term "shock organs" to indicate 

 the organs or tissues in which evidence of hypersensitiveness ap- 

 pears. Thus in vasomotor rhinitis the ''shock organ" is the mu- 

 cous membrane of the nose, in asthmas it is the lungs, while in 

 eczema, contact dermatitis, etc., it is the skin. Duke and others 

 report numerous cases of allergy in which the "shock organ" is 

 the gastrointestinal tract. Coca calls attention to the fact that 

 not all of the shock organs are affected in every atopic patient. 

 Many hay fever patients do not have asthma and conversely some 

 patients with asthma do not have hay fever or urticaria. 



Inheritance Factors in Atopy. — Cooke and Vender Veer seem 

 to have established an hereditary factor for the clinical allergies 

 other than serum disease and contact dermatitis (poison ivy, etc.). 

 Their data indicate that the capacity to become allergic is an in- 

 heritable characteristic which follows the Mendelian principles. 

 There is no evidence to indicate that hypersensitiveness to a 

 specific substance is inherited ; instead only the capacity to become 

 allergic appears in the offspring. A parent may suffer from hay 

 fever due to ragweed pollen while the offspring may develop eczema 

 from eating eggs. There is no unanimity of opinion at present as 

 to whether the hereditary character is dominant or recessive. Such 



559 



