525 16 Pesticides and Skin Diseases in Man Radoslaw Spiewak 16.1 Introduction The skin is the largest organ of the human body. With a surface area of 1.5–2 m 2 and thickness of 0.5–5 mm, it amounts to 15% of the total body weight. Thanks to its com- plexity and unique multilayer structure, this versatile organ forms an extremely effec- tive barrier against a range of external factors—from solar irradiation to microbes and from mechanical trauma to xenobiotics and irritants (Spiewak 1998). Its durabil- ity is warranted by its continuous regeneration. The outermost layer of the skin—the epidermis—is fully renewed every 3–4 weeks, a process referred to as “epidermal cycle.” The function of an effective barrier between the internal environment and the external infuence is not the only purpose of the largest organ—the skin also takes active part CONTENTS 16.1 Introduction ........................................................................................................................ 525 16.2 Problems with Terminology............................................................................................. 526 16.3 Effects of Pesticides in the Skin ....................................................................................... 526 16.4 Pesticides and Autoimmunity ......................................................................................... 527 16.5 Pesticide-Related Skin Diseases....................................................................................... 528 16.5.1 Chemical Burns ...................................................................................................... 528 16.5.2 Irritant Contact Dermatitis ................................................................................... 528 16.5.3 Phototoxic Contact Dermatitis ............................................................................. 528 16.5.4 Allergic Contact Dermatitis.................................................................................. 532 16.5.5 Photoallergic Contact Dermatitis ........................................................................ 533 16.5.6 Urticaria................................................................................................................... 533 16.5.7 Erythema Multiforme ........................................................................................... 533 16.5.8 Erythema Dyschromicum Perstans (Ashy Dermatosis) .................................. 533 16.5.9 Acne ......................................................................................................................... 533 16.5.10 Porphyria Cutanea Tarda ................................................................................... 534 16.5.11 Pigmentation Disorders ...................................................................................... 534 16.5.12 Nail Disorders ...................................................................................................... 534 16.5.13 Hair Disorders ..................................................................................................... 535 16.5.14 Nonmelanoma Skin Cancer ............................................................................... 535 16.5.15 Melanoma ............................................................................................................. 536 16.6 Concluding Remarks ......................................................................................................... 536 Acknowledgment ........................................................................................................................ 536 References..................................................................................................................................... 536