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- Presentation
What to Do if Patch Testing is Negative: Contact Dermatitis Mimickers
Description
In this presentation on negative patch testing and contact dermatitis mimickers, the speaker discusses the challenges of diagnosing cases where patch tests yield no reactions. Using a case of a retired cosmetologist as an example, they highlight that despite normal patch tests, dermatological conditions such as metastatic disease may present similarly. The speaker emphasizes the importance of thorough differential diagnosis and considers alternatives such as biopsies and relevant lab tests to explore systemic diseases. Literature reveals that roughly one-third of patients undergoing patch testing report negative results, often presenting with conditions like irritant contact dermatitis or psoriasis. Factors such as age, gender, and race may affect these outcomes. The speaker shares personal experiences from their practice, underscoring various case studies where patients presented with distinct symptoms but tested negative for allergens. Key approaches include reviewing the patient’s history, considering systemic issues, and utilizing skin scrapings or flow cytometry when necessary. The session concludes by reinforcing the notion that negative patch tests are common and should lead to continued investigation rather than diagnostic stagnation.
View moreConclusions
- Patch testing can yield negative results in a significant portion of patients (about 31.3%), particularly in younger, male, non-white individuals.
- Negative patch tests are associated with various diagnoses, including irritant contact dermatitis, atopic dermatitis, and other dermatoses.
- Pre-test probability and appropriate counseling are crucial before conducting patch tests.
- In cases of negative patch tests, other diagnostic approaches such as skin biopsies, lab testing, and a thorough medication history should be considered.
- Eyelid dermatitis is less likely to result in negative patch tests compared to other skin regions, while generalized dermatitis tends to correlate with higher rates of negative results.
- Common practices after negative patch testing include ordering lab tests and revisiting patient history to reassess the diagnosis and explore alternative treatments.
- Multiple biopsies may provide additional insights into the dermatitis diagnosis by enabling clonality studies and assessing for malignancies.
- Treatment options for patients with dermatitis that did not respond to patch testing include immunosuppressive therapies and phototherapy.
- Assessing accompanying symptoms and reviewing medication histories is essential to rule out systemic issues or drug reactions that may contribute to dermatological conditions.
- Taylor J. S., Maibach H. I., Mathias T., Sasseville D. Patients with negative patch tests: Retrospective analysis of North American Contact Dermatitis Group (NACDG) data 2001-2016. JAAD 2019.
- Spiker A., Mowad C. M. Evaluation and Management of Patch Test-Negative Patients With Generalized Dermatitis. Dermatitis 2016.
- Nedorost S. Negative patch test rates. Clinical Dermatology 2018.
- Starck et al. Retrospective series of 694 patients in Brazil from 2013 - 2018. Clinical Dermatology 2022.
- Starck et al. Distribution of patients with negative patch tests according to the final diagnosis. Anais Brasileiros de Dermatologia 2022;97(6):798-822.
- Abel et al. Immunological eruptions of ageing/atopic dermatitis in older adults/eczema of immunosenescence. BJD 2021.