Clinical Features

Allergic contact dermatitis is generally confined to the site of the contact with the allergen.  A complicating factoring diagnosis can often be that symptoms appear on parts of the skin where the patient cannot recall or does not report any contact with the suspected allergen.  Care should be taken, particularly where the contact with the allergen has been on the hands, not to misdiagnose as often the other sites on which the symptoms may appear may be secondary, with the allergen having been transferred to those sites from the hands. 

Only small quantities of the allergen are necessary to prompt the reaction and the reaction may be an onset condition where the patient has previously had no difficulty with contact with the allergen.
 
The presentation of the skin usually includes the following features:-

(a)       Redness;

(b)       Swelling;

(c)        Blistering;

(d)       Dryness; and

(e)       Bumpiness.

Some common allergens are:-

(a)       Nickel, often a component in jewellery;

(b)       Fragrances;

(c)        Preservatives;

(d)       Rubber, such as in gloves;

(e)       Dyes and colorants;

(f)        Adhesives; and

(g)       Topical medications such as sunscreens.


The above list is far from exhaustive but rather illustrative to assist in diagnosis in a practical setting.
 
Treatment of allergic contact dermatitis usually involves two stages.

Firstly, identifying the allergen and eliminating it from the patient's environment.  Secondly, management of the symptoms and asymptomatic.  If the allergen has not been identified correctly and eliminated from the patient's environment then symptoms are likely to be reoccurring.  Allergic contact dermatitis, as such can only be managed, not cured.