Atopic dermatitis

Characteristic Features

The word ‘atopy,’ which was introduced by Coca in1923, is a combination of ‘a’ and ‘topia’, which mean without and place, respectively. Therefore, atopy means a disease without a place, which is a new disease entity. Allergic reactions (Type I or IV) are not solely responsible for atopic dermatitis, as it was formerly thought. Multiple and diverse factors contribute to the onset of atopy. It is also called ‘a strange disease’ because its cause cannot be identified as a previously known allergic reaction. Atopic dermatitis is associated with atopic diathesis, which is sensitivity to pollen, ticks, house dust, or animal dander. Pollinosis (hay fever), asthma and urticaria are usually caused by hereditary atopic diathesis (see previous page). Clinical features of atopic dermatitis include a red face, Denie’s line of the lower eyelid and dry itchy skin. White dermographism and acetylcholine delayed blanch phenomenon are regarded as abnormal blood vessel reactions which never occur in normal people. The tendency of atopic persons to have such reactions to various kinds of substances has been attributed to the onset of atopic diseases. Also these abnormal reactions are responsible for the tendency to vasoconstriction. Even if a skin test is positive, or if the concentration of IgE antibodies is extremely high, it is not always possible to conclude that these are the causes of atopic dermatitis.

Adult-type Atopic Dermatitis

It is recognized that adult-type atopic dermatitis, characterized by a reddish face, is recently increasing in number. The reddish face is accompanied by reddish lesions and edematous or acne-like papules, both of which are intensely itchy and become exudative and crusted. Misuse of corticosteroid ointment is blamed as a cause of atopic red face. In addition, stress, lack of self-control (e.g., irregular sleeping and eating patterns) and immaturity (over dependency on parents) tend to make the disease worse. Adult-type atopic dermatitis is so difficult to cure that atopic patients sometimes become depressed and come to distrust their doctors. They may soon stop using the corticosteroid ointment and become dependent on so called “atopy businesses” which offer miracle cures. As a result, the patients’ dermal symptoms gradually get worse.

For a long time it was considered that stress was an important factor, which aggravated atopic dermatitis. For example, students preparing for college entrance exams got better after success, when relieved from their mental stress. Another example is that of a Tokyo resident whose atopic dermatitis disappeared when she went back home to the countryside. I believe that there is no doubt that stress has something to do with the cause of adult-type atopic dermatitis, but that there is some additional pathogenesis, an example of which is a contact dermatitis caused by chemical sensitivity (to be discussed later.).

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