Immediate contact skin reactions, an update of contact urticaria, contact urticaria syndrome and protein contact dermatitis - "A never ending story"

Listening and paying attention to our patients is crucial for understanding a disease. A good example is Immediate Contact Skin Reactions (ICSR) which manifest as Contact Urticaria Syndrome (CUS), Contact Urticaria (CU) and Protein Contact Dermatitis (PCD). These entities are characterized by the immediate skin development of itchy flares, wheals, and/or dermatitis. All conditions usually appear within minutes of contact with various substances, including chemicals, animal products, antibiotics, cosmetics, and many other materials. From the clinical and diagnostic viewpoint, the patient's clinical report is critical to its description, definition and classification. Its pathogenesis still remains a challenge and our knowledge of the agents potentially responsible is slowly increasing over time, based on the descriptions of a few isolated cases. This text reviews the classic concepts, introduces new compounds responsible for these immediate skin reactions, and suggests further investigation.