Table of Contents
1 The International Contact Dermatitis Research Group J.-M. Lachapelle H.I. Maibach 1
1.1 Historical Background 1
1.2 Current Tasks of the ICDRG 2
1.3 ICDRG Members 2
References 3
Part I Patch Testing
2 The Spectrum of Diseases for Which Patch Testing is Recommended J.-M. Lachapelle 7
2.1 Allergic Contact Dermatitis 7
2.1.1 Pathomechanisms in Allergic Contact Dermatitis 7
2.1.2 Clinical Signs and Symptoms 9
2.1.3 Histopathological Features 11
2.2 The Allergic Contact Dermatitis Syndrome 12
2.2.1 Stage 1 of ACDS 14
2.2.2 Stage 2 of ACDS 16
2.2.3 Stage 3 of ACDS 18
2.3 Allergic Contact Dermatitis vs. Irritant Contact Dermatitis: Criteria for Differential Diagnosis 22
2.4 Other Skin Diseases in Which Patch Testing is of Major Interest 23
2.5 An Algorithmic Approach: The Key Role of Patch Testing 24
2.6 Hand Dermatitis: Procedures Applied in Differential Diagnosis 24
2.6.1 Hand Dermatitis: Exogenous and Endogenous Factors 24
2.6.2 A Classification of Hand Dermatitis 24
2.6.3 Tools of Investigation 29
2.6.4 Hand Dermatitis: Some Examples of an Algorithmic Approach 29
2.6.5 Management of Chronic Hand Dermatitis 29
References 31
3 Patch Testing Methodology J.-M. Lachapelle H.I. Maibach 33
3.1 Historical Background 33
3.2 Definition and Aims 34
3.2.1 Requirements for an Ideal Patch Testing Procedure 34
3.2.2 Is Patch Testing the "Gold Standard" to Investigate Patients with Allergic Contact Dermatitis? 34
3.3 Patch Test Units 35
3.3.1 Finn Chamber 35
3.3.2 Plastic Square Chambers 37
3.3.3 Reinforcement of Patch Test Units 39
3.4 A General Overview of Allergens 39
3.4.1 Allergens 39
3.4.2 Bioavailability ofAllergens 41
3.4.3 Quality Control of Allergens 42
3.4.4 Appropriate Amounts of Petrolatum to be Applied at Patch Testing 42
3.4.5 Appropriate Amounts of Liquids to be Applied at Patch Testing 42
3.5 Specific Recommendations when Considering Patch Testing Patients 42
3.5.1 Patch Testing on Intact Skin is Critical 43
3.5.2 Medicaments and Patch Testing 43
3.5.3 Pregnancy and Patch Testing 44
3.5.4 Patch Testing in Children 44
3.6 Application of Patch Tests on the Skin: Some Practical Suggestions 45
3.6.1 Test Sites 45
3.6.2 Removal of Hair 46
3.6.3 Degreasing of Test Site 46
3.6.4 Application of Test Strips 46
3.6.5 Instructions to Patients 46
3.7 Reading Time 46
3.7.1 Standard Patch Test Occlusion and Reading Time 47
3.7.2 Conventional Patch Test Reading Time 47
3.7.3 Reading at Day 2, Day 3, Day 4 47
3.7.4 Reading at Day 7 47
3.7.5 Single Reading vs. Multiple Reading 48
3.7.6 Day 3 vs. Day 4 Reading 48
3.7.7 One-Day Occlusion vs. Two-Day Occlusion 48
3.7.8 Marking the Skin 48
3.7.9 Immediate Urticarial Reactions to Some Allergens 49
3.8 Reading and Scoring Patch Test Results 50
3.8.1 Nomenclature: Scoring Codes 50
3.8.2 Rating Patch Test Reactions Based on Digital Images 50
3.8.3 Some Remarks About Reading and Scoring 50
3.9 Irritant Patch Test Reactions 54
3.10 False-Positive Patch Test Reactions 56
3.11 False-Negative Patch Test Reactions 57
3.12 Compound Allergy 57
3.13 Cross-Sensitization, Concomitant Sensitization, Polysensitization 58
3.13.1 Cross-Sensitization 58
3.13.2 Concomitant Sensitization 59
3.13.3 Polysensitization 59
3.14 Unwanted Adverse Reactions of Patch Testing 59
3.14.1 Patch Test Sensitization ("Active Sensitization") 61
3.14.2 Excited Skin Syndrome ("Angry Back") 61
3.15 Patch Test Readings in Different Ethnic Populations 62
3.15.1 Patch Test Reading in Oriental Populations 62
3.15.2 Patch Test Reading in Black Populations 63
3.16 Patch Testing Techniques in Different Climatic Environments 64
3.16.1 Temperate Climates 65
3.16.2 Tropical Climates 65
3.16.3 Patch Testing Procedures in the Tropics 65
3.17 Additional Note: Proposal for Modified Scoring Codes of Positive Patch Test Reactions 66
References 67
4 The Standard Series of Patch Tests J.-M. Lachapelle 71
4.1 Historical Background 71
4.2 Advantages and Disadvantages of Using a Standard Series of Patch Tests 72
4.2.1 Advantages 72
4.2.2 Disadvantages 72
4.3 The Three Major Standard Series Used Throughout the World 72
4.4 Some Remarks About the "Mixes" of the Standard Series 73
4.5 Proposal for an ICDRG Revised International Series of Patch Tests 73
4.6 List of Allergens Proposed for an Extended ICDRG Series, Which May be Required According to Each Individual Situation 77
4.7 List of Allergens Proposed to Be Deleted from the Revised and Extended ICDRG Series 77
4.8 Succinct Information about Allergens 78
4.8.1 Allergens Listed in Sect. 4.5 78
4.8.2 Allergens Listed in Sect. 4.6 80
4.9 Additional Series of Patch Tests 81
References 81
5 Photopatch Testing J.-M. Lachapelle A. Goossens 83
5.1 Definition and Aims 83
5.2 Photoallergic Contact Dermatitis 83
5.3 Photoallergic Contact Dermatitis vs. Airborne Allergic Contact Dermatitis: Criteria for Differential Diagnosis 86
5.4 Photoallergic Drug Eruptions 86
5.5 Photopatch Testing Methodology 86
5.6 Light Sources 87
5.7 Proposal for a Photopatch Test Series 87
References 88
6 The TRUE Test System J.-M. Lachapelle H. I. Maibach 89
6.1 Introduction 89
6.2 The TRUE Test System 89
6.3 The Standard TRUE Test Series 90
6.4 Methodology of Use 91
6.5 Regulatory Information 92
6.6 Additional Practical Information 94
6.7 Conventional Patch Testing vs. TRUE Test: The Current Situation 94
References 97
7 Additional Testing Procedures J.-M. Lachapelle H.I. Maibach 99
7.1 Stripping Test 99
7.2 Open Test 99
7.3 Semi-Open Test 100
7.4 Repeated Open Application Test 102
7.5 Testing Procedures with Unknown Substances 103
7.5.1 Strategy 104
7.5.2 Steps Required Prior to Any Testing Procedure 104
7.5.3 Testing Procedures with Solid Products and Extracts 105
7.5.4 Testing Procedures with Cosmetics and Other Related Products 106
7.6 Oral Provocation Test (Oral Challenge) 106
7.7 Other Investigations 107
7.7.1 pH Measurement 107
7.7.2 Spot Tests 107
7.7.3 Chemical Analysis 110
References 110
8 Clinical Relevance of Patch Test Reactions J.-M. Lachapelle H.I. Maibach 113
8.1 Introduction 113
8.2 General Principles 113
8.3 Past and Current Relevance 114
8.4 Scoring System 114
8.5 Strategies 115
8.5.1 Clinical History 116
8.5.2 Environmental Evaluation 117
8.5.3 Further Correlations 118
8.5.4 Additional Investigations 118
8.6 Suggestions for Improved Evidence-Based Diagnosis of Relevance 119
References 120
9 The Atopy Patch Test in Atopic Dermatitis U. Darsow J. Ring 121
9.1 Introduction 121
9.2 Atopy Patch Test Technique 122
9.3 Atopy Patch Test Reading 123
9.4 Atopy Patch Test Relevance, Patient Subgroups, and Pitfalls 124
References 126
Part II Prick Testing
10 The Spectrum of Diseases for Which Prick Testing and Open (Non-Prick) Testing are Recommended J.-M. Lachapelle H.I. Maibach 131
10.1 The Contact Urticaria Syndrome 131
10.1.1 Clinical Symptoms and Stages of CUS 131
10.1.2 Etiology and Mechanisms of CUS 134
10.1.3 Contact Urticaria to Natural Rubber Latex 136
10.2 Protein Contact Dermatitis 137
References 139
11 The Methodology of Open (Non-Prick) Testing, Prick Testing, and its Variants J.-M. Lachapelle H.I. Maibach 141
11.1 Open (Non-Prick) Testing 141
11.2 Prick Test: Technical Modalities and Reading 141
11.2.1 Technique of Puncture 142
11.2.2 Control Solutions 143
11.2.3 Reading Time 143
11.2.4 Reading Prick Test Results 143
11.2.5 Medicaments and Prick Testing 144
11.2.6 False-Negative Reactions 144
11.2.7 False-Positive Reactions 145
11.2.8 Prick Tests in Children and Babies 145
11.3 Prick-by-Prick Test 145
11.4 Scratch Test 145
11.5 Scratch-Chamber Test 146
11.6 Comparative Indications of Open (Non-Prick) Testing, Prick Testing, and Other Related Tests 146
11.7 Intradermal Testing 146
11.8 Prick Testing: Allergens of Interest for Skin Problems 147
11.8.1 Latex 147
11.8.2 Airborne Environmental per Annum Allergens 148
11.8.3 Airborne Environmental Seasonal Allergens 148
11.8.4 Food Allergens (Trophallergens) 149
11.8.5 Occupational Allergens 149
11.8.6 Fungi 149
11.8.7 Miscellaneous (Immunological and/or Non-Immunological) Urticariogens 150
References 151
Part III Testing in Cutaneous Systemic Adverse Drug Reactions: Interest and Limitations
12 Testing Procedures in Cutaneous Systemic Adverse Drug Reactions J.-M. Lachapelle 155
12.1 General Considerations 155
12.2 Tools of Investigation in CADR 155
12.3 Histopathological Limitations in Diagnosis of a CADR 156
12.4 Patch Testing in CADR 156
12.4.1 The Spectrum of CARDs for Which Patch Testing is Recommended 157
12.4.2 The Spectrum of CARDs for Which Patch Testing can be Performed (Being Still Controversial) 160
12.4.3 The Spectrum of CARDs for Which Patch Testing is of No Interest 160
12.4.4 Guidelines in Drug Patch Testing: General Rules 160
12.4.5 Technical Aspects of Drug Patch Testing 161
12.4.6 Readings of Drug Patch Tests 163
12.4.7 False-nagative Patch Test Reactions 163
12.4.8 False-Positive Patch Test Reactions 164
12.5 Prick Testing in CADR 165
12.5.1 Intradermal Testing in CADR 165
12.5.2 Oral Provocation Test (Oral Challenge) in CADR 165
References 166
Appendix J.-M. Lachapelle 167
A.1 Introductory Remarks 167
A.2 Bakery Series 168
A.3 Corticosteroid Series 169
A.4 Cosmetic Series 171
A.5 Epoxy Resin Series 173
A.6 Hairdressing Series 175
A.7 Isocyanate Series 176
A.8 Metals Series 177
A.9 (Meth) Acrylate Series 177
A.10 Plastics and Glues Series 178
A.11 Rubber Additives Series 179
A.12 Textile Dyes and Finish Series 180
A.12.1 Disperse Dyes 182
A.12.2 Other Dyes 183
A.12.3 Textile Finish Resin Allergens 183
A.13 Other Series 183
A.13.1 Shoe Dermatitis 183
A.13.2 Plant Dermatitis 184
References 188
Suggested Reading 189
Index 191
