Anais Brasileiros de Dermatologia

Anais Brasileiros de Dermatologia

Volume 96, Issue 6, November–December 2021, Pages 706-711
Anais Brasileiros de Dermatologia

Original Article
Usefulness of dermoscopy in the evaluation of patch test reactions,☆☆

https://doi.org/10.1016/j.abd.2021.04.006Get rights and content
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open access

Abstract

Background

Despite being widely used in different areas of dermatology, there have been few studies evaluating the benefit of dermoscopy in the interpretation of patch tests, especially in weak and doubtful reactions.

Objectives

To evaluate the role of dermoscopy in the interpretation of patch tests and describe the main findings of the reactions.

Method

Prospective study, carried out in dermatology reference centers in southern Brazil, which evaluated the final results of patch tests analyzed with the aid of dermoscopy.

Results

77 patients and 160 reactions were included. The most prevalent substances were nickel sulphate (23.8%), kathon CG (9.4%), and perfume mix (8.8%). The main dermoscopic findings were reaction area​​ greater than half of the chamber site (90%), homogeneous erythema (86.9%), vesicles (30%), crusts (21.3%), perifollicular erythema (35%), pore reaction (19.4%) and pustules (8.8%). Dermoscopy was found to facilitate the definition of erythema in reactions on black skin and when due to substances with deposition of pigment. Of the 64 weak or doubtful reactions, 36 (56.25%) showed a change in the final result after dermoscopy evaluation; of the 36 doubtful reactions, 33 (91.6%) showed a change in the final result after dermoscopy evaluation (p < 0.001).

Study limitations

The probable limitation of the study is its sample size. Though certain significance levels have been reached, other possible relationships may not have been observed.

Conclusion

Dermoscopy improves significantly the interpretation of patch tests, especially in weak and doubtful reactions.

Keywords

Allergic contact, dermatitis
Dermoscopy
Patch tests

Cited by (0)

How to cite this article: Oppermann K, Cattani CAS, Bonamigo RR. Usefulness of dermoscopy in the evaluation of patch test reactions. An Bras Dermatol. 2021;96:706–11.

☆☆

Study conducted at the Ambulatório de Dermatologia Sanitária do Rio Grande do Sul/ Service of Dermatology, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.