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The outcome of an additional patch‐test reading on days 6 or 7
Author(s) -
Jonker Maureen J.,
Bruynzeel Derk P.
Publication year - 2000
Publication title -
contact dermatitis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 96
eISSN - 1600-0536
pISSN - 0105-1873
DOI - 10.1034/j.1600-0536.2000.042006330.x
Subject(s) - patch test , patch testing , allergen , retrospective cohort study , medicine , contact dermatitis , chemistry , dermatology , allergy , surgery , immunology
In a retrospective study (period 1997–1998), the usefulness of an additional patch‐test reading on day (D) 6 or 7 was investigated. In 62 out of 760 patients (8.2%), 77 late‐positive reactions, those manifest after D3, were seen. 4 late reactions of allergens of which a related allergen reacted earlier (at D2 or D3) in the same patient were not incorporated in the study as late‐positive. Allergens most involved in producing late‐positive reactions were nickel sulfate (20 reactions), neomycin sulfate (7), tixocortol‐21‐pivalate (5), p.t. butylphenol formaldehyde resin (5) and Cl+Me isothiazolinone (5). Special attention is paid to ?+ reactions at D6 or D7, because these reactions could add extra information to the outcome of patch‐test readings, considering that this might be a group of allergens that has been positive between D3 and D6/7 or become positive later on. When this group is included, the total number of late‐positive reactions is 105 in 88 out of 760 patients (11.6%). By doing D3 readings in combination with D6 or D7 readings only, one would miss 24 positive reactions. However, we concluded that it was preferable to have a reading on D2 and D3. An extra reading on D6 or D7 is very useful as it gives additional information in 8.2% of patch‐tested patients.