How to manage drug-virus interplay underlying skin eruptions in children

The majority of viral rashes occurring during an antibiotic therapy are considered as a drug hypersensitivity reaction (DHR). Differentiating a viral rash versus a DHR is difficult or even impossible. In delayed DHRs the interplay between viruses and drugs is summarized according to the recent literature. The question is if the same reaction will again occur in case of drug re-exposure in absence of the concomitant viral infection because of persistent immune reactivity. Epstein Barr Virus (EBV) and Human Herpes virus 6 (HHV-6) models are analyzed in case of maculopapular exanthemas (MPEs) and drug reaction with eosinophilia and systemic symptoms (DRESS) over a course of drug therapy. MPEs are the most common skin manifestation during a viral infection and a concomitant drug therapy. In type IVb reactions to drugs a hapten/pro-hapten mechanism and a pharmacological interaction (p-i mechanism) are described as the 2 major ways to make T cells response functional. Rarely the altered repertoire model is involved. The Human Leukocyte Antigen (HLA) predisposition is an additional essential factor that can facilitate DHR. In MPEs rarely a DHR is confirmed by allergy testing. Severity and duration of MPEs, the presence of eosinophilia and systemic symptoms make more reliable the persistent nature of the reaction. Research on this topic is needed in order to provide the clinicians with instruments to decide when to suspect future reactions upon drug re-exposure even in the absence of a viral infection, because those patients should be investigated by a complete drug allergy work up.

75% negative skin test results in patients with suspected hypersensitivity to beta-lactam antibiotics: Influencing factors and interpretation of test results

Background

The diagnostic approach for beta-lactam (BL) drug hypersensitivity reactions (DHR) is based on the history, clinical signs, skin tests (ST), in vitro tests, and drug provocation tests (DPT). The aim of this study was to assess the performance of an allergy workup with ST in a real-world use.

Methods

In this cross-sectional study the rate of positive ST in subjects with suspected DHR to penicillins and cephalosporins was investigated. Of special interest were correlations of ST positivity: 1) to the time intervals between index reaction and the allergic work-up, 2) time interval from drug exposure to the onset of signs, 3) pattern of manifestation in delayed DHR and involvement of test area in the index reaction, and 4) potential advantage of patch testing in delayed DHR.

Results

175 patients were included between January 2018 and April 2019 (63.4% female), 45 (25.7%) with immediate DHR manifestation and 130 with delayed DHR manifestation (74.3%). A total of 44 patients (25.1%) had a positive ST (immediate DHR 37.8% versus 20.0% in delayed DHR). ST positivity decreased in both groups after 3 years from 47.8% [95%CI 29.2-67] to 23.5% [95%CI 9.6-47.3] in immediate DHR and 23.0% [95%CI 15-4-32.9] to 12.9% [95%CI 5.1-28.9] in delayed DHR. The proportion of positive ST was higher in patients with more severe forms of delayed DHR, and in subjects with a shorter latency period of onset of symptoms after drug exposure: 0-3d: 29.5% [95%CI 19.6-41.9] vs. >3d: 11.6% [95%CI 6.0-21.2]). No sensitization was shown in delayed urticaria or angioedema. ST done outside the skin area involved during the index reaction were negative in all cases (0/38 vs. 26/84 in cases with involved area). The combination of patch test and intradermal test (IDT) revealed an additional positive result in 2/77 cases. Additional in vitro testing reduced the proportion of negative test results to 72%.

Conclusion

In most patients with negative test results, we could not clarify the cause of the BL-associated adverse events even with further investigations (including DPT). How to prevent new drug-induced adverse events in such patients has hardly been investigated yet. Corresponding cohort studies could improve the data situation.

Update on Quinolone Allergy

PURPOSE OF REVIEW

Quinolones are a group of synthetic antibiotics widely use as first-line treatment for many infections. There has been an increase in the incidence of hypersensitivity reactions to quinolones in recent years, likely due to increased prescription. The purpose of this review is to summarize the clinical pictures, the methods used for diagnosing and the management of allergic reactions to quinolones.

RECENT FINDINGS

Allergic reactions to quinolones can be immediate or delayed, being anaphylaxis and maculopapular exanthema respectively the most frequent clinical entities. A precise diagnosis is particularly difficult since clinical history is often unreliable, skin tests can induce false-positive results, and commercial in vitro test are not well validated. Therefore, drug provocation testing is considered the gold standard to establish diagnosis, which is not a risk-free procedure. Cross-reactivity between quinolones is difficult to predict due to the small number of patients included in the few published studies. Moreover, hypersensitivity to quinolones has also been associated with beta-lactam and neuromuscular blocking agent allergies, although further studies are needed to understand the underlying mechanisms. Avoidance of the culprit quinolone is indicated in patients with a diagnosis of hypersensitivity to these drugs. When quinolone treatment is the only therapeutic option available, desensitization is necessary. This review summarizes the complex diagnostic approach and management of allergic reactions to quinolones.

Vision-threatening bilateral panuveitis and TRAPS in a child: an uncommon association

PURPOSE

To report a childhood case of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) carrying the R92Q variant with a vision-threatening bilateral panuveitis.

METHODS

Case report and review of the literature.

RESULTS

A 7-year-old boy presented with an active bilateral panuveitis and a macular rash associated with fever. Fundus examination showed two choroidal lesions on the posterior pole of the right eye, and fluorescein angiography revealed early hypofluorescence and late hyperfluorescence of the lesions, which were hyper-autofluorescent. Extensive clinical laboratory analyses ruled out autoimmune diseases and systemic infection. The only remarkable finding was a positive IgG for herpes simplex 1. He underwent two successive diagnostic pars plana vitrectomies as well as cataract and glaucoma surgeries. Genetic analysis revealed a mutation in the TNFRSF1A gene, and the patient was diagnosed with TRAPS-associated bilateral panuveitis. He was treated with adalimumab and has been free of active inflammation since then.

CONCLUSIONS

We present here the first case reported of panuveitis in a patient with TRAPS. This finding stresses the increasing importance of genetic analysis in search of autoinflammatory diseases to establish an adequate diagnosis and treatment in cases of uveitis of unknown etiology.

[Zika virus infection: A review]

Zika Virus (ZIKV), originally identified in 1947, is a re-emerging Flavivirus transmitted mainly through bites by Aedes mosquitos. Until the recent outbreaks in the Pacific islands and Central and South America, it was known to cause benign disease, in most cases asymptomatic or with mild and nonspecific symptoms (fever, rash, conjunctivitis, arthralgia, etc.). The unprecedented current epidemic has highlighted new modes of transmission (through blood, perinatally and sexually) as well as serious neurological complications such as congenital defects in the fetuses of infected mothers and Guillain-Barre syndrome in adults. This situation, coupled with the threat of worldwide spread, prompted the WHO to declare the ZIKV a public health emergency of international concern in February 2016.

Multiple Drug Hypersensitivity

Multiple drug hypersensitivity (MDH) is a syndrome that develops as a consequence of massive T-cell stimulations and is characterized by long-lasting drug hypersensitivity reactions (DHR) to different drugs. The initial symptoms are mostly severe exanthems or drug rash with eosinophilia and systemic symptoms (DRESS). Subsequent symptoms due to another drug often appear in the following weeks, overlapping with the first DHR, or months to years later after resolution of the initial presentation. The second DHR includes exanthema, erythroderma, DRESS, Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), hepatitis, and agranulocytosis. The eliciting drugs can be identified by positive skin or in vitro tests. The drugs involved in starting the MDH are the same as for DRESS, and they are usually given in rather high doses. Fixed drug combination therapies like sulfamethoxazole/trimethoprim or piperacillin/tazobactam are frequently involved in MDH, and 30-40% of patients with severe DHR to combination therapy show T-cell reactions to both components. The drug-induced T-cell stimulation appears to be due to the p-i mechanism. Importantly, a permanent T-cell activation characterized by PD-1+/CD38+ expression on CD4+/CD25low T cells can be found in the circulation of patients with MDH for many years. In conclusion, MDH is a drug-elicited syndrome characterized by a long-lasting hyperresponsiveness to multiple, structurally unrelated drugs with clinically diverse symptoms.

[Uncommon cutaneous presentation of visceral Leishmaniasis associated with HIV]

BACKGROUND

Visceral leishmaniasis is not normally expressed in skin. Herein, we describe the case of an HIV-positive patient who developed two unusual skin manifestations during an episode of visceral leishmaniasis.

PATIENTS AND METHODS

A 48-year-old female patient consulted initially for infiltrated purpura of all four limbs. Skin biopsy revealed leukocytoclastic vasculitis with Leishman-Donovan bodies. Laboratory tests showed medullary, splenic, gastric and colic involvement, suggesting systemic disease, and enabling visceral leishmaniasis to be diagnosed. Two years later, despite prolonged treatment, the patient presented maculopapular exanthema, and histology revealed persistent Leishman-Donovan bodies.

DISCUSSION

We report herein an association of two rare skin manifestations in an HIV-positive patient with visceral leishmaniasis: infiltrated purpura and maculopapular exanthema. However, the underlying mechanisms remain hypothetical. The initial leukocytoclastic exanthema could be secondary to either polyclonal hypergammaglobulinaemia or to IgA deposits, or possibly to mechanical impairment of blood vessels by the actual parasite. The maculopapular exanthema occurring later raised the possibility of post-Kala-Azar leishmaniasis due to blood-borne dissemination in an anergic subject or perhaps even immune reconstitution inflammatory syndrome.

Allopurinol desensitization with A 2 weeks modified protocol in an elderly patients with multiple comorbidities: a case report

Background

Allopurinol is an effective urate-lowering drug that is well tolerated by the majority of patients. Patients with chronic renal insufficiency have an increased risk of hypersensitivity reactions with allopurinol.

Case presentation

75 year old male patient with gout, renal insufficiency, history of metastatic colorectal carcinoma status post-resection was referred to Allergy clinic for a maculopapular eruption that developed 1 week after initiating therapy with allopurinol. The rash resolved with discontinuation of allopurinol. However, his serum urate level rose to 19.9 mg/dl. We initially proposed a slow 4 week oral allopurinol desensitization. The treating nephrologist felt it was critical to lower urate more rapidly. As a result, we modified the dose and standard 4 week protocol down to 2 weeks. A suspension of allopurinol was prepared by the allergy nurse practitioner with a 300 mg allopurinol tablet. The sensitization protocol was modified as a starting dose of 0.3 mg escalating to a final dose of 300 mg/day in 2 weeks. There was no reaction during or after the desensitization. The patient’s urate level normalized (6.3 mg/dl) and has continued on 300 mg allopurinol daily without reaction.

Conclusion

A 2 week modified allopurinol desensitization protocol is a safe alternative for elderly patients with multiple comorbidities.

Predictive markers for carbamazepine and lamotrigine-induced maculopapular exanthema in Han Chinese

The aims of this study were to clarify the possible associations of carbamazepine (CBZ)- and lamotrigine (LTG)-induced maculopapular exanthema (MPE) with the human leukocyte antigen (HLA) alleles in Chinese patients. A total of 249 subjects, including 40 patients with CBZ-induced MPE (CBZ-MPE), 43 patients with LTG-induced MPE (LTG-MPE), 52 CBZ-tolerant controls, 42 LTG-tolerant controls and 72 healthy controls, were included in this study. High-resolution HLA genotyping was performed by a specific kit. Differences in the allele frequencies among the groups were assessed. The allele frequencies of HLA-A*0201 and HLA-DRB1*1405 were significantly higher (P=0.033 and P=0.003, respectively), but those of HLA-B*5801 and HLA-DRB1*0301 (P=0.037 and P=0.024, respectively) were lower in the CBZ-MPE patients when compared with the CBZ-tolerant group. We also observed two significantly increased alleles of HLA-A*3001 and HLA-B*1302 (P=0.013 and P=0.013, respectively) and a decreased allele of HLA-A*3303 (P=0.048) in the LTG-MPE patients when compared with those in the LTG-tolerant group. Our results support the hypothesis that these HLA alleles contribute to the genetic susceptibility to CBZ/LTG-MPE and may be valuable as potential biomarkers for CBZ/LTG-MPE in Han Chinese.