Fixed drug eruptions in children

Skin eruptions in children: Drug hypersensitivity vs viral exanthema

Childhood rashes or exanthemas are common and are usually relatively benign. There are many causes of rash in children, including mainly viruses, and less often bacterial toxins, drugs, allergens and other diseases. Viral exanthema often appears while children are taking a medication in the course of a viral infection; it can mimic drug exanthema and is perceived as a drug allergy in 10% of cases. In the vast majority of cases, the distinction between virus-induced and drug-induced skin eruption during the acute phase is not possible. The drugs most commonly implicated are beta-lactams (BL) and non-steroidal anti-inflammatory drugs (NSAIDs). Viruses, commonly Epstein-Barr virus (EBV), human herpesvirus 6 (HHV6) and cytomegalovirus (CMV), and the bacterium, Mycoplasma pneumoniae, may cause exanthema either from the infection itself (active or latent) or because of interaction with drugs that are taken simultaneously. Determination of the exact diagnosis requires a careful clinical history and thorough physical examination. Haematological and biochemical investigations and histology are not always helpful in differentiating between the two types of exanthema. Serological and polymerase chain reaction (PCR) assays can be helpful, although a concomitant acute infection does not exclude drug hypersensitivity. A drug provocation test (DPT) is although considered the gold standard for the diagnosis and is not preferred by the patients. Skin tests are not well tolerated, and in vitro tests, such as the basophil activation test and lymphocyte transformation, are of low sensitivity and specificity and their relevance is debatable. Based on current evidence, we propose a systematic clinical approach for timely differential diagnosis and management of rashes in children who present a cutaneous eruption while receiving a drug.

Acetaminophen-induced generalized fixed drug eruption in a 5-year-old girl

Acetaminophen is one of the most widely prescribed analgesic drugs. Fixed drug eruption, especially the pigmenting type, is reported in literature as a possible adverse event to acetaminophen in child. We hereby present a case of generalized fixed drug eruption due to acetaminophen intake in a 5-year-old dark-skinned child.

Pediatric drug eruptions

Drug eruptions in children are common but in general less studied than their adult counterparts. Aside from having significant impact on the child's health and quality of life, these reactions can limit what medications the patient can receive in the future. Familiarity with pediatric drug eruptions is important for accurate diagnosis and to prevent future recurrence or ineffective therapy. Our current understanding of how drug reactions differ mechanistically between children and adults is poor. There are multiple factors that could be contributing to the differing incidence, presentation, and treatment modalities offered to pediatric versus adult patients. For many of these cutaneous drug reactions, the treatment regime is not standardized, being based primarily on case reports. Although not comprehensive, this review highlights common pediatric drug eruption patterns and discuss diagnostic mimickers. Five cutaneous adverse drug reactions in the pediatric population are presented: morbilliform (exanthematous) eruptions, urticarial eruptions, serum sickness-like reactions, fixed drug eruptions, and DRESS syndrome. Clinical features, diagnostic workup, and management are discussed with an emphasis on the pediatric population.

Common Annular Lesions in the Pediatric Population: Part 2

Rash is a common chief complaint for patients presenting to their physician, especially within the pediatric field. The ability to distinguish characteristics of a rash, including morphology, distribution, and configuration, is critical to forming the differential diagnosis. This is the second article of a 2-part review that discusses the common rashes that present in an annular configuration. This articles discuss the presentation, diagnosis, and treatment of fixed drug eruptions, lupus erythematosus, erythema multiforme, urticaria, and erythema migrans. Although this review is not inclusive of all conditions that present with annular lesions, it can serve as a starting point for physicians managing a patient with these complaints. [Pediatr Ann. 2019;48(3):e135-e138.].

Genome-Wide Association Study in Immunocompetent Patients with Delayed Hypersensitivity to Sulfonamide Antimicrobials

Background

Hypersensitivity (HS) reactions to sulfonamide antibiotics occur uncommonly, but with potentially severe clinical manifestations. A familial predisposition to sulfonamide HS is suspected, but robust predictive genetic risk factors have yet to be identified. Strongly linked genetic polymorphisms have been used clinically as screening tests for other HS reactions prior to administration of high-risk drugs.

Objective

The purpose of this study was to evaluate for genetic risk of sulfonamide HS in the immunocompetent population using genome-wide association.

Methods

Ninety-one patients with symptoms after trimethoprim-sulfamethoxazole (TMP-SMX) attributable to “probable” drug HS based on medical record review and the Naranjo Adverse Drug Reaction Probability Scale, and 184 age- and sex-matched patients who tolerated a therapeutic course of TMP-SMX, were included in a genome-wide association study using both common and rare variant techniques. Additionally, two subgroups of HS patients with a more refined clinical phenotype (fever and rash; or fever, rash and eosinophilia) were evaluated separately.

Results

For the full dataset, no single nucleotide polymorphisms were suggestive of or reached genome-wide significance in the common variant analysis, nor was any genetic locus significant in the rare variant analysis. A single, possible gene locus association (COL12A1) was identified in the rare variant analysis for patients with both fever and rash, but the sample size was very small in this subgroup (n = 16), and this may be a false positive finding. No other significant associations were found for the subgroups.

Conclusions

No convincing genetic risk factors for sulfonamide HS were identified in this population. These negative findings may be due to challenges in accurately confirming the phenotype in exanthematous drug eruptions, or to unidentified gene-environment interactions influencing sulfonamide HS.

Drug hypersensitivity in children: report from the pediatric task force of the EAACI Drug Allergy Interest Group

When questioned, about 10% of the parents report suspected hypersensitivity to at least one drug in their children. However, only a few of these reactions can be confirmed as allergic after a diagnostic workup. There is still a lack of knowledge on drug hypersensitivity (DH) epidemiology, clinical spectrum, and appropriate diagnostic methods particularly in children. Meanwhile, the tools used for DH management in adults are applied also for children. Whereas this appears generally acceptable, some aspects of DH and management differ with age. Most reactions in children are still attributed to betalactams. Some manifestations, such as nonsteroidal anti-inflammatory drug-associated angioedema and serum sickness-like reactions, are more frequent among young patients as compared to adults. Risk factors such as viral infections are particularly frequent in children, making the diagnosis challenging. The practicability and validity of skin test and other diagnostic procedures need further assessment in children. This study presents an up-to-date review on epidemiology, clinical spectrum, diagnostic tools, and current management of DH in children. A new general algorithm for the study of these reactions in children is proposed. Data are presented focusing on reported differences between pediatric and adult patients, also identifying unmet needs to be addressed in further research.

The diagnosis and management of antibiotic allergy in children: Systematic review to inform a contemporary approach

BACKGROUND

Adverse drug reactions (ADRs) to antibiotics are commonly reported among children, with some representing genuine drug allergies. Accurate diagnostic tests are required. Drug provocation testing (DPT) is accepted as the gold standard investigation among children with suspected antibiotic allergy. We conducted this review to ascertain the strength of current evidence for using DPT as the first-line investigation for suspected antibiotic allergy among children.

METHODS

Medline was searched in June 2014 for publications investigating antibiotic allergy among children.

RESULTS

865 publications were retrieved and 76 studies selected. ADRs are most common among children of 0-4 years, however only some reveal drug allergies. The best evidence demonstrates that around 0.21% of general paediatric outpatients demonstrate positive antibiotic intradermal (ID) testing or DPTs, while 6.8% of children attending emergency departments for suspected β-lactam allergy may fulfil DPT reactions. Four studies used DPT-based protocols to investigate suspected antibiotic allergy, with two of these conducting ID testing and DPTs across all participants. β-lactam and clarithromycin ID testing had sensitivities of 66.7% and 75%, with positive predictive values of 36% and 33%, respectively, when compared with DPT data.

CONCLUSIONS

Our literature review found four (6%) publications that performed DPTs to subjects' index antibiotic across all participants. No rigorous evidence supports using skin prick, ID or in vitro diagnostic testing; indeed, the testing regimens, extracts and positivity criteria used are inconsistent. We recommend that suspected non-serious antibiotic allergy should be primarily investigated using DPT-based clinical protocols. Data examining their safety, acceptability and diagnostic performance are required.

Evaluation of polymorphisms in the sulfonamide detoxification genes NAT2, CYB5A, and CYB5R3 in patients with sulfonamide hypersensitivity

OBJECTIVE

To determine whether polymorphisms in the sulfonamide detoxification genes, CYB5A (encoding cytochrome b(5)), CYB5R3 (encoding cytochrome b(5) reductase), or NAT2 (encoding N-acetyltransferase 2) were over-represented in patients with delayed sulfonamide drug hypersensitivity, compared with control patients who tolerated a therapeutic course of trimethoprim-sulfamethoxazole without adverse event.

METHODS

DNA from 99 nonimmunocompromised patients with sulfonamide hypersensitivity who were identified from the Personalized Medicine Research Project at the Marshfield Clinic, and from 99 age-matched, race-matched, and sex-matched drug-tolerant controls, were genotyped for four CYB5A and five CYB5R3 polymorphisms, and for all coding NAT2 SNPs.

RESULTS

CYB5A and CYB5R3 SNPs were found at low allele frequencies (<3-4%), which did not differ between hypersensitive and tolerant patients. NAT2 allele and haplotype frequencies, as well as inferred NAT2 phenotypes, also did not differ between groups (60 vs. 59% slow acetylators). Finally, no difference in NAT2 status was found in a subset of patients with more severe hypersensitivity signs (drug reaction with eosinophilia and systemic symptoms) compared with tolerant patients.

CONCLUSION

We found no evidence of a substantial involvement of these nine CYB5A or CYB5R3 polymorphisms in sulfonamide hypersensitivity risk, although minor effects cannot be completely ruled out. Despite careful medical record review and full resequencing of the NAT2 coding region, we found no association of NAT2 coding alleles with sulfonamide hypersensitivity (predominantly cutaneous eruptions) in this adult Caucasian population.

Cutaneous reactions to drugs in children

Cutaneous eruptions are a commonly reported adverse drug reaction. Cutaneous adverse drug reactions in the pediatric population have a significant impact on patients' current and future care options. A patient's recollection of having a "rash" when they took a medication as a child is a frequent reason for not prescribing a particular treatment. The quick detection and treatment of cutaneous adverse drug reactions, plus identification of the causative agent, are essential for preventing the progression of the reaction, preventing additional exposures, and ensuring the appropriate use of medications for both the current condition and others as the patient ages. The purpose of this review is to discuss a reasonable approach to recognition and initial management of cutaneous adverse drug reactions in children.

Hypersensitivity reactions in neonates and infants

Although rare, several hypersensitivity reactions can occur in the infant population. Several types of hypersensitivity reactions are discussed, including urticaria, drug eruptions, erythema multiforme, allergic contact dermatitis, and vasculitis (acute hemorrhagic edema of infancy); neonatal lupus also is discussed. Although most of these conditions are benign, their presentations can be dramatic and a cause of concern for both parents and physicians. Important considerations and differences in the diagnosis and management of these conditions in children under the age of 6 months are discussed.

ADVERSE REACTIONS OF NITROFURANTOIN, TRIMETHOPRIM AND SULFAMETHOXAZOLE IN CHILDREN

PURPOSE

Many children with urological disease require long-term treatment with antibiotics. In many cases the choice of medical instead of surgical management hinges on the implied safety of certain drugs. Recently some groups have advocated subureteral injection procedures to avoid long-term antibiotics for low grade reflux. We present a concise and relevant review on the use and adverse reactions of nitrofurantoin, trimethoprim and sulfamethoxazole in children.

MATERIALS AND METHODS

We reviewed the literature regarding the safety and toxicity of these drugs. Information regarding absorption, excretion and dosing was also gathered to explain better the mechanisms of toxicity.

RESULTS

Adverse reactions in children reported in the literature related to nitrofurantoin are gastrointestinal disturbance (4.4/100 person-years at risk), cutaneous reactions (2% to 3%), pulmonary toxicity (9 patients), hepatoxicity (12 patients and 3 deaths), hematological toxicity (12 patients), neurotoxicity and an increased rate of sister chromatid exchanges. Adverse reactions in children related to trimethoprim/sulfamethoxazole are almost exclusively due to the sulfamethoxazole component, including cutaneous reactions (1.4 to 7.4 events per 100 person-years at risk), hematological toxicity (0% to 72% of patients) and hepatotoxicity (5 patients). The majority of adverse reactions were found in children on full dose therapy and not prophylaxis.

CONCLUSIONS

The use of nitrofurantoin, trimethoprim and sulfamethoxazole is safe in children for long-term prophylactic therapy. The antibiotic safety issue should not be misconstrued as an argument for surgical therapy, whether minimally invasive or not. Adverse reactions exist to these medicines but they are less common than seen in adults, presumably because of the lower dose used for therapy, and the lack of significant comorbidities and drug interactions in children. Serious side effects are extremely rare and most are reversible by discontinuing therapy. The extremely low potential for significant adverse reactions should be discussed with parents.

Fixed drug eruption in the genital area in 15 boys

Fixed drug eruption (FDE) is manifested as localized, circumscribed, round or oval plaques that characteristically recur in the same site with each use of the offending drug. The drugs most commonly implicated are phenolphthalein, barbiturates, antibiotics, salicylates, contraceptives, and anticonvulsants. FDE can appear on different parts of the body. The sites of predilection are the lips, genitalia, and sacral area. There are no reports of large series of pediatric patients with FDE involving the genitalia. We describe 15 boys with genital FDE associated with several drugs. Their average age at diagnosis was 3.2+/-2.2 years (range 6 months-8 years). The clinical presentation usually consisted of swelling and erythema of the penis and/or scrotum associated with pruritus, restlessness, urinary retention, and painful micturation. The diagnosis was supported by clinical history. The causative drugs were identified and confirmed by a provocation test, resolution after the drug was stopped, and a positive migration inhibiting factor (MIF) test. Genital FDE in children is uncommon, but the drugs associated with this entity are in such widespread use in pediatric practice that its recognition may be important, especially considering its easy treatability.

Fixed drug eruptions. Incidence, recognition, and avoidance

Drug eruptions often have nonspecific clinical findings, and the evaluation of the probability of an eruption being a drug-induced event is difficult. A few types of drug eruption do not present such problems, and the fixed drug eruption is one of those whose clinical findings are specific enough to allow a diagnosis. The fixed drug eruption is a commonly reported type of drug eruption. The incidence of fixed drug eruptions has tended to increase, although the overall number of drug eruption cases has decreased. This is one of the reasons why fixed drug eruptions are familiar to dermatologists. The most characteristic findings of a fixed drug eruption are recurrence of similar lesions at the same sites and healing with residual hyperpigmentation. The residual hyperpigmentation serves as an indicator of site recognition. Diagnosis is not always easy; for example, as is the case for nonpigmenting fixed drug eruptions, which do not have any residual hyperpigmentation. The development of molecular biology may help to clarify the pathogenesis of fixed drug eruptions, but the reason for their recurrence on the same sites is still unknown. Identification of the causative drug or drugs is essential for the management of fixed drug eruptions, as it is for other drug eruptions. The causative drug or drugs and cross-reactants should be avoided to prevent recurrence. To date, rechallenge is the most reliable method of identifying causative drugs, but increasingly the use of skin tests has gained the attention of investigators. The validity and the problems of skin tests are discussed, and an approach to the clinical management of fixed drug eruptions is presented.