Proteins as allergens are mainly responsible for IgE-dependent allergic cli
nical manifestations. The organs affected by a given protein are relatively
specific according to the possible airborne nature of these allergens. Cut
aneous penetration, theoretically more difficult, is favoured by more intim
ate contacts and especially by a pre-existing alteration of the skin. Other
more organ specific diseases and more complex mechanisms are also possible
, such as contact dermatitis to proteins and extrinsic allergic alveolitis.