Features Common to Respiratory and Dermal Allergies

The remainder of this section will focus in more detail on Type I (immediate) and Type IV (delayed) hypersensitivity with emphasis on the lung and skin as target organs. In both cases the adverse effects of hypersensitivity develop in two stages  

Mast cells Histamine Smooth muscle contraction Increased vascular permeability Vascular constriction Mucus production 

Eosinophils Major basic protein (MBP) Eosinophil peroxidase (EPO) Eosinophil cationic protein (ECP) Microbial killing, tissue damage 

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