Diagnosing Allergic Contact Dermatitis Through Elimination, Perception, Detection and Deduction

Abstract

Several authors have commented upon the skills of detection required in making a diagnosis of allergic contact dermatitis. Here, we emphasise the search for clues in a systematic manner. We describe four stages as part of a systematic method for diagnosing allergic contact dermatitis. Firstly, elimination (or inclusion) of non-allergic diagnoses. Secondly, perception: the pre-patch test diagnosis and the 'three scenarios' principle. Thirdly, detection: optimising the sensitivity of the patch test process. Fourthly, deduction: diagnosing allergic contact dermatitis by associating the dermatitis with the allergen exposure. We further compare and contrast the pre-patch test history and examination with the markedly different one ('microhistory' and 'microexamination') used after patch testing. The importance of knowledge of contact dermatitis literature is emphasised with a review of recent publications. Finally, we also highlight the use of contact allergy profiling as an investigative tool in the diagnosis of allergic contact dermatitis.

Microexamination

“…Examining images stored on patients’ phones of flares of their dermatoses introduces a third, temporal aspect to the examination. Diagnostic clues from history and examination are then combined with the results of patch testing to deduce the presence of allergic contact dermatitis . To enhance this analytical approach, a good understanding of contact dermatitis literature and acquisition of clinical experience in patch testing are also required …”

“…We have previously introduced the concept of “microexamination” to describe a systematic approach to cutaneous examination combined with attention to minute detail . Here, we characterise this further by using microexamination of the hands as an example.…”

“…clues from history and examination are then combined with the results of patch testing to deduce the presence of allergic contact dermatitis. 2 To enhance this analytical approach, a good understanding of contact dermatitis literature and acquisition of clinical experience in patch testing are also required. 2 We have previously introduced the concept of "microexamination" to describe a systematic approach to cutaneous examination combined with attention to minute detail.…”

“…2 To enhance this analytical approach, a good understanding of contact dermatitis literature and acquisition of clinical experience in patch testing are also required. 2 We have previously introduced the concept of "microexamination" to describe a systematic approach to cutaneous examination combined with attention to minute detail. 2 Here, we characterise this further by using microexamination of the hands as an example.…”

“…2 We have previously introduced the concept of "microexamination" to describe a systematic approach to cutaneous examination combined with attention to minute detail. 2 Here, we characterise this further by using microexamination of the hands as an example. This should include the sequential assessment of 10 locations: Table 1 shows examples of different allergic and non-allergic dermatoses in relation to the various examination points of the hands.…”