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Background: Few studies have evaluated allergy workup in fixed drug eruption (FDE) in a large population., Objective: To evaluate the sensitivity of a standardized allergy workup for diagnosing the cause of FDE, with a focus on in situ repeated open application tests (ROATs)., Methods: In a retrospective multicenter study, we analyzed the practice of conducting a complete allergy workup for the etiological diagnosis of FDE. It consisted of 3 steps: in situ patch tests (PTs) for all cases except pure mucosal involvement, followed by in situ ROAT if in situ PT results were negative, and finally a drug challenge (DC). The in situ ROAT involved daily application of the suspected drug on a previously affected FDE site for 7 days., Results: Of 98 suspected FDE cases, 61 patients (median age 61 y; male-to-female ratio 1.8) with a complete allergy workup were included. In 4 cases, even the DC yielded negative results. Among the remaining 57 patients with a positive workup, implicated drugs included paracetamol (12 cases), β-lactams (11 cases), imidazoles (9 cases, including 5 with metronidazole), nonsteroidal anti-inflammatory drugs (8 cases), iodinated contrast media (4 cases), cotrimoxazole (3 cases), and various other drugs in 10 patients. The diagnosis was confirmed by in situ PT in 17 of 54 cases (31.5%), in situ ROAT in 14 of 40 cases (35%) (with 4 cases showing remote reactivation of FDE sites), and DC in 26 cases., Conclusions: The sequential allergy workup involving successively in situ PT, in situ ROAT, and DC is a reliable and safe method for diagnosing the cause of FDE. In situ tests exhibited a sensitivity of over 50%., (Copyright © 2024. Published by Elsevier Inc.)

In the setting of an acute cutaneous adverse drug reaction there is increasing interest in selected phenotypes and hosts to continue drug therapy, especially in settings in which there are limited therapeutic options. This concept of "treating through," defined as the continued use of a drug in the setting of, in particular maculopapular exanthema, potentially avoids unnecessary drug discontinuation. A review of the recent literature, historical viewpoints, and expert opinion are provided within to form recommendations and algorithms for a "treating-through" approach., (Copyright © 2021 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Currently used antimalarial drugs (AM) are hydroxychloroquine and chloroquine, which are prescribed for many autoimmune disorders. The value of skin tests on cutaneous adverse drug reactions (CADR) with AM remains unknown., Objective: The main objective of this retrospective study is to know whether skin tests for AM are useful and how to manage the recovery of AM therapy in these patients., Methods: All patients referred for suspected CADR secondary to AM between 2001 and 2014 in eight French dermatology centers were retrospectively reviewed., Results: We report herein a retrospective series of 20 patients with CADR and AM involvement. Skin tests, performed in 14/20 patients, were negative in all cases. Six patients had an oral provocation test with recurrence of CADR in 1 case., Conclusion: We encourage dermatologists to perform oral provocation tests in nonsevere CADR in order to allow AM rechallenge at progressive doses., (© 2015 S. Karger AG, Basel.)

Background: Delayed allergic hypersensitivity reactions have classically been described as type IV reactions, which are caused by T cells; however, the respective roles of CD4(+) and CD8(+) cells are yet to be defined. A central role for CD8(+) cytotoxic T cells as effector cells has been suggested., Objectives: To determine the type of T cell involved in corticosteroid allergy., Methods: We analysed the kinetics of T cell recruitment and the cytokine production profile in positive patch tests of 27 corticosteroid-sensitized patients, as compared with control sites and control subjects. Skin biopsies, collected at 8, 24 and 48 hr following drug application, were embedded in paraffin for histological and immunohistological staining, and, in some cases, also deep-frozen for gene expression analyses., Results: CD3(+) T cells were rapidly recruited in concert with the positivity of the patch test sites. High levels of interleukin (IL)-4, IL-5 and, to a lesser extent, interferon-γ suggested that both Th2 and Th1 cytokines were implicated. IL-4 was also produced by γδ T cell receptor (TCR) lymphocytes., Conclusions: This study showed that, in allergic contact dermatitis caused by corticosteroids, the inflammatory infiltrate is composed of CD3(+) T cells with a predominant Th2 cytokine profile, among which IL-4 is also produced by γδ TCR lymphocytes., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Skin tests, including patch tests (PTs), prick tests, and intradermal tests (IDTs), are useful in identifying the culprits of cutaneous adverse drug reactions (CADRs), and determining safer, alternative drugs. PTs have a low sensitivity but are valuable in investigating maculopapular exanthema (MPE), as well as severe CADR, including toxic epidermal necrolysis (TEN), Stevens‐Johnson syndrome (SJS), and in particular, acute generalized exanthematous pustulosis (AGEP), and drug reaction with eosinophilia and systemic symptoms (DRESS). To ensure their specificity, at least 10 control tests should be performed. Prick tests are mainly used in the evaluation of immediate‐type hypersensitivity and can be performed with all drugs, except opiates. IDTs can be used to explore immediate and delayed‐type hypersensitivity, if an injectable form of the drug exists. Except for SJS/TEN, IDTs should be performed by injecting 0.02 mL of the drug. We here provide a practical, up‐to‐date review on the use of these skin tests in the work‐up of CADRs. Numerous negative controls for drug PTs, as well as criteria for the immediate and delayed positivity of prick tests and IDT, are included. It should be emphasized that a negative result never excludes the potential responsibility of a drug in a CADR. [ABSTRACT FROM AUTHOR]

Of the seven patients in this subset, six had further injections and only one relapsed, although less severely, and two patients presented with different cutaneous reactions following the next injection. Only two patients had a classical Sweet syndrome histology showing a diffuse dermal neutrophilic infiltrate, while two had a dermal infiltrate of histiocyte-like immature myeloid cells compatible with histiocytoid Sweet syndrome (Figure 1c, d). Sweet-like syndrome and multiple COVID arm syndrome following COVID-19 vaccines: "specific" patterns in a series of 192 patients. [Extracted from the article]

This article discusses the emergence of doxycycline-induced fixed drug eruption (FDE), a common adverse reaction characterized by red patches on the skin or mucosa. FDE is typically associated with drugs like paracetamol, antibiotics, and non-steroidal anti-inflammatory drugs. However, recent cases have shown that doxycycline, commonly used for post-exposure prophylaxis (PeP) against sexually transmitted infections (STIs), can also induce FDE. The article presents 15 cases of doxycycline-induced FDE, with most cases occurring within the past 6 months. The authors recommend in situ repeated open application tests (ROAT) to confirm the diagnosis and avoid oral provocation tests (OPT), which can carry risks. They also suggest that all cyclin antibiotics, including doxycycline, be contraindicated for safety reasons. The article emphasizes the importance of recognizing doxycycline-induced FDE, particularly in cases of genital lesions that could be misdiagnosed as STIs. [Extracted from the article]