chapter  2
26 Pages

Photoprotection

Why Do We Need Photoprotection? 20

The Solar Spectrum 20

Acute Solar Damage 21

Introduction 21

Mechanism of Acute Photodamage 22

Histology of Acute Photodamage 22

Chronic Solar Damage 23

Introduction 23

Mechanism of Chronic Damage 23

Histology of Chronic Damage 24

Other Effects of Photoexposure 24

Photosensitive Reaction 24

Phototoxicity 26

Photoallergy 27

Photosensitivity Skin Disorders 27

Lupus Erythematosus (290-330 nm) 27

Xeroderma Pigmentosum (290-340 nm) 27

Chronic Actinic Dermatitis (290-360 nm) 27

Polymorphous Light Eruption (290-365 nm) 29

Hydroa Vacciniforme (290-400 nm) 29

Persistent Light Reaction (290-400 nm) 29

Solar Urticaria (290-515 nm) 29

Porphyrias (400-410 nm) 29

Miscellaneous Dermatoses 29

Carcinogenesis Related to Photoexposure 30

Mechanism of Carcinogenesis 30

Opportunities to Interrupt the Pathway 31

Initiation 31

Promotion 31

Progression 33

Immunopathology of Skin Cancer-An Apparent Paradox 33

Strategies to Block UV Light 34

Sun Exposure Avoidance 34

Sun Protective Clothing 34

Sunscreens 36

Sunscreening Agents 37

Organic Sunscreening Agents 37

Inorganic Sunscreening Agents 37

Proper Use of Sunscreens 38

Suggestions for the Future 38

References 39

WHY DO WE NEED PHOTOPROTECTION?