Clinical relevance of doubtful reactions in patch testing : A single-centre retrospective study

© 2024 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd..

BACKGROUND: Doubtful reactions in patch testing are infrequently reported in the literature; however, recent reports have suggested they be assessed with the same scrutiny as stronger reactions.

OBJECTIVE: Assess the clinical relevance of doubtful reactions in patch testing.

METHODS: Retrospective study of 1514 patients comprehensively patch tested via the NACDG standard series and additional allergens based on history. The clinical relevance of each reaction was graded based on the NACDG scale: definite, probable, possible, past, unknown and irritant. Reactions were considered 'unique' if an additional mild-to-strong reaction to the same chemical at a different concentration was not observed.

RESULTS: 68.9% (1043) of patients demonstrated at least 1 doubtful reaction. Of 4453 total doubtful reactions, 92.2% (4106) were unique. Only 3.3% (137) and 12.2% (500) of these were determined to be of definite or probable clinical relevance respectively. 'Fragrance' was the most common allergen family present among the unique definite doubtful reactions (37). However, 24 (64.9%) of these also had a stronger reaction to another fragrance. Cocamidopropyl betaine was the second most frequent allergen demonstrating definite doubtful reactions (27) and unique in 85.2% (23) of cases. Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) was most prevalent (36) but less frequently unique (58.3%, 21).

CONCLUSIONS: Doubtful reactions may not be as impactful to clinical decision making as theorised in the literature. Few demonstrate definite clinical significance, and many have related stronger reactions that capture them for clinical purposes. Identification of doubtful reactions to cocamidopropyl betaine and MCI/MI may be of greatest significance as they most frequently were not supported by stronger reactions.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - year:2024

Enthalten in:

Contact dermatitis - (2024) vom: 21. Feb.

Sprache:

Englisch

Beteiligte Personen:

Arora, Puneet [VerfasserIn]
Brumley, Caroline [VerfasserIn]
Hylwa, Sara [VerfasserIn]

Links:

Volltext

Themen:

Allergic contact dermatitis
Borderline reaction
Clinical relevance
Doubtful reaction
Journal Article
Macular erythema
Patch test

Anmerkungen:

Date Revised 21.02.2024

published: Print-Electronic

Citation Status Publisher

doi:

10.1111/cod.14526

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM36872087X