Anticonvulsant hypersensitivity syndrome in children: incidence, prevention and management

DRESS Syndrome Secondary to Carbamazepine Therapy Presenting with Bilateral Acute Anterior Uveitis and Angle Closure Glaucoma

Purpose

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare, life-threatening multi-system adverse drug reaction characterized by febrile skin rash, hematologic abnormalities, and involvement of internal organs. We report a case of DRESS syndrome in a child presenting with primary ophthalmic manifestations.

Case Report

An 11-year-old boy presented with severe pain and diminished vision in both eyes six weeks after starting carbamazepine therapy for seizure disorder. Ocular examination revealed features of bilateral acute anterior uveitis, acute onset myopia, and angle closure glaucoma secondary to uveal effusion. Additionally, the patient was febrile with a generalized maculopapular rash, and blood investigations revealed eosinophilic leukocytosis. A diagnosis of carbamazepine-induced DRESS syndrome was made, and carbamazepine therapy was discontinued. Treatment with cycloplegics, topical, and systemic steroids resulted in prompt clinical recovery.

Conclusion

Ophthalmologists should be aware that hypersensitivity to anticonvulsants, such as carbamazepine, can present with bilateral uveitis and uveal effusion along with systemic symptoms. Prompt diagnosis and treatment can prevent vision loss and life-threatening complications. Patients should be counselled about potential adverse effects of anticonvulsants before therapy.

Use of the Biopharmaceutics Drug Disposition Classification System (BDDCS) to Help Predict the Occurrence of Idiosyncratic Cutaneous Adverse Drug Reactions Associated with Antiepileptic Drug Usage

Cutaneous adverse reactions (CARs) from antiepileptic drugs (AEDs) are common, ranging from mild to life-threatening, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). The identification of subjects carrying the HLA-B*15:02, an inherited allelic variant of the HLA-B gene, and the avoidance of carbamazepine (CBZ) therapy in these subjects are strongly associated with a decrease in the incidence of carbamazepine-induced SJS/TEN. In spite of the strong genetic associations, the initiation of hypersensitivity for AEDs is still not very well characterized. Predicting the potential for other AEDs to cause adverse reactions will be undoubtedly beneficial to avoid CARs, which is the focus of this report. Here, we explore the use of the Biopharmaceutics Drug Disposition Classification System (BDDCS) to distinguish AEDs associated with and without CARs by examining the binding relationship of AEDs to HLA-B*15:02 and data from extensive reviews of medical records. We also evaluate the lack of benefit from a Hong Kong population policy on the effects of screening for HLA-B*15:02 and previous incorrect structure-activity hypotheses. Our analysis concludes that BDDCS class 2 AEDs are more prone to cause adverse cutaneous reactions than certain BDDCS class 1 AEDs and that BDDCS Class 3 drugs have the lowest levels of cutaneous adverse reactions. We propose that BDDCS Class 3 AEDs should be preferentially used for patients with Asian backgrounds (i.e., Han Chinese, Thai, and Malaysian populations) if possible and in patients predisposed to skin rashes.

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.

Drug-Induced Hypersensitivity Syndrome Due to Anticonvulsants in a Two-Year-Old Boy

Drug-induced hypersensitivity syndrome (DIHS) usually refers to severe cutaneous drug eruption associated with systemic involvement and potentially fatal outcome. We report a 2-year-old Caucasian boy who developed DIHS due to phenytoin and phenobarbital and who showed extensive internal organ involvement. We are alerting that failure to recognize this drug eruption and discontinue the culprit drug may result in increased severity, greater extent of internal organ involvement, and fatal outcome. The recent research about the influence of human herpesvirus 6 co-infection on the pathogenesis of DIHS is also discussed by the authors in this paper.

Phenobarbital-induced severe cutaneous adverse drug reactions are associated with CYP2C19*2 in Thai children

BACKGROUND

Aromatic anticonvulsant-induced severe cutaneous adverse drug reactions (SCARs), including Stevens-Johnson syndrome (SJS), toxic epidermal necrosis (TEN), and drug rash with eosinophilia and systemic symptoms (DRESS), are fatal immune-mediated adverse drug reactions. CYP2C19, a cytochrome P450 isoform, plays a role in metabolic rate of aromatic anticonvulsant. HLA-B*1502 has also been demonstrated to be associated with carbamazepine-induced SJS-TEN.

METHODS

Forty case patients who were diagnosed with SCARs after initiation of phenobarbital (PB), phenytoin (PHT), or carbamazepine (CBZ) for 1-8 wk and forty control patients who received PB, PHT, or CBZ at least 2 months with no adverse drug reactions were enrolled in the study. The genotypes of CYP2C19*1, CYP2C19*2, and HLA-B*1502 were analyzed using allele-specific polymerase chain reaction technique. Clinical characteristics of SCARs patients who used different drugs were also analyzed.

RESULTS

There was no significant difference in sex, onset of symptoms, laboratory results, treatment, and length of stay among patients with SCARs due to PB, PHT, or CBZ. The patients with CYP2C19*2 variant had a trend to have a likelihood to develop SCARs more than the patients with CYP2C19 wild type (OR = 2.5, 95% CI (0.96-67.3) p = 0.06). In subgroup analysis, the patients with CYP2C19*2 variant were at four times increased risk of SCARs from phenobarbital more than the patients with CYP2C19 wild type (OR = 4.5, 95% CI (1.17-17.37) p < 0.03). There was no association between the HLA-B*1502 and aromatic anticonvulsant-induced severe cutaneous adverse reactions (SCARs).

CONCLUSION

CYP2C19*2 variant may play a role in the genetic predisposition of SCARs from phenobarbital.

Pathogenesis and Clinical Approaches to Anticonvulsant Hypersensitivity Syndrome: Current State of Knowledge

Anticonvulsant hypersensitivity syndrome (AHS) is a rare, but severe and potentially fatal, adverse reaction that occurs in patients who are treated with commonly used older anticonvulsant drugs (phenytoin, carbamazepine and phenobarbital) and/or with some newer agents (lamotrigine). Paediatric patients are at an increased risk for the development of AHS for the higher incidence of seizure disorder in the first decade of life. Hypersensitivity reactions range from simple maculopapular skin eruptions to a severe life-threatening disorder. AHS is typically associated with the development of skin rash, fever and internal organ dysfunctions. Recent evidence suggests that AHS is the result of a chemotoxic and immunologically-mediated injury, characterized by skin and mucosal bioactivation of antiepileptic drugs and by major histocompatibility complex-dependent clonal expansion of T cells. Early recognition of AHS and withdrawal of anticonvulsant therapy are essential for a successful outcome. In vivo and vitro tests can be helpful for the diagnosis that actually depends essentially on clinical recognition.

Anticonvulsant hypersensitivity syndrome treated with intravenous immunoglobulin

Anticonvulsant hypersensitivity syndrome is a severe, potentially life-threatening, reaction to the aromatic anticonvulsant medications. Reported here is a case of anticonvulsant hypersensitivity syndrome secondary to phenobarbital in a 2-year-old boy; he responded to drug withdrawal, corticosteroids, and intravenous immunoglobulin. The literature regarding treatment of this syndrome is reviewed.

Photochemical reactions involved in the phototoxicity of the anticonvulsant and antidepressant drug lamotrigine (Lamictal)

Lamotrigine (LTG) [3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine], an anticonvulsant and antidepressant drug Lamictal, produces a (photo)toxic response in some patients. LTG absorbs UV light, generating singlet oxygen (1O2) with a quantum yield of 0.22 in CH2Cl2, 0.11 in MeCN and 0.01 in D2O. A small production of superoxide radical anion was also detected in acetonitrile. Thus, LTG is a moderate photosensitizer producing phototoxicity and oxidizing linoleic acid. LTG is a weak 1O2 quencher (k(q) = 3.2 x 10(5) M(-1) s(-1) in MeCN), but its photodecomposition products in dimethyl sulfoxide (DMSO) quenched 1O2 very efficiently. Upon intense UV irradiation from a xenon lamp, LTG was photobleached rapidly in DMSO and slowly in acetonitrile, alcohol and water. The rate increased significantly when laser pulses at 266 nm were employed. The photobleaching products generated 1O2 twice as strongly as LTG. Photobleaching was usually accompanied by the release of chloride anions, which increased in the presence of ascorbic acid. This suggests the formation of aryl radicals via dechlorination, a process which may be responsible for the photoallergic response observed in some patients. Our results demonstrate that LTG is a moderate generator of 1O2 prone to photodechlorination, especially in a reducing environment, which can contribute to the reported phototoxicity of LTG.

Tendon sheath abscess and severe carbamazepine hypersensitivity

We report a 10-year-old girl with enthesitis and Staphylococcus aureus tendon sheath abscess as complications of severe carbamazepine hypersensitivity. Our patient had an adverse reaction to intravenous immunoglobulin and this, as well as the use of corticosteroids, may have contributed to her condition.

Probable Anticonvulsant Hypersensitivity Syndrome Due to Fosphenytoin in a Pediatric Patient with Streptococcus pneumoniae Meningitis

An 8-year-old previously healthy girl with Streptococcus pneumoniae meningitis developed probable anticonvulsant hypersensitivity syndrome (AHS) within 5 days of starting fosphenytoin. She experienced fever, rash, periorbital edema, profound hepatotoxicity and coagulopathy. Her sudden and dramatic rise in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) to greater than 80 times the upper limit of normal in combination with an elevated INR were very concerning. Mortality from AHS has been correlated with the degree of hepatic involvement. Fosphenytoin was immediately discontinued and, within 48 hours, AST, ALT and INR began to decrease and were within normal limits by hospital day 23. Prompt recognition of probable AHS and immediate discontinuation of fosphenytoin resulted in an abrupt reversal of clinical signs and laboratory values associated with potential hepatic failure in a pediatric patient.

Drug-induced hypersensitivity syndrome in a premature infant

Fever, skin reactions, and limb edema because of drug-induced hypersensitivity have been reported in children because of various drugs, mainly aromatic antiepileptic drugs such as phenytoin, phenobarbital, carbamazepin, and primidone. The skin reactions differ in severity and range from mild maculopapular erythema to exfoliative dermatitis. They have been described in older children but have not been reported in newborn infants. We report a premature newborn infant who developed fever, skin reactions, and edema because of phenytoin while receiving anticonvulsant therapy.

Genetic aspects of immune-mediated adverse drug effects

Adverse drug effects (ADEs) are of great importance in medicine and account for up to 5% of all hospital admissions. ADEs can arise from several mechanisms and a wide range of drugs can cause immune-mediated ADEs (IMADEs). For a drug to elicit an IMADE, it must be both immunogenic (that is, able to sensitize the immune system) and antigenic (that is, able to evoke a response from a sensitized immune system). Unlike protein therapeutics, small-molecule drugs (or xenobiotics) are usually neither immunogenic nor antigenic. IMADEs are therefore the result of complex interactions between drug-metabolizing enzymes, immune sensitization and immune effectors. The genetic aspects of this interplay are discussed in this review.

Anticonvulsant Hypersensitivity Syndrome: Lymphocyte Toxicity Assay for the Confirmation of Diagnosis and Risk Assessment

OBJECTIVE

To report a case of anticonvulsant hypersensitivity syndrome (AHS) precipitated by exposure to phenobarbital.

Case Summary

An 11-year-old girl receiving phenobarbital developed fever, exfoliative skin rash, mucous membrane lesions, alopecia, and hepatic inflammation. Investigations ruled out an infectious etiology; an adverse event following phenobarbital administration was considered. Applying the Naranjo probability scale for objective causality assessment showed the adverse reaction was probably due to phenobarbital. The diagnosis was confirmed by in vitro lymphocyte toxicity assay, which demonstrated increased cell death following exposure to phenobarbital, as well as other aromatic anticonvulsants and lamotrigine.

DISCUSSION

AHS is a rare, potentially fatal event with multisystem manifestations. It is reported following exposure to aromatic antiepileptics. The mechanism proposed for AHS is accumulation of toxic arene oxide metabolites due to a defect in epoxide hydrolase—mediated detoxification. Despite the difference in chemical structure of lamotrigine, in vitro susceptibility to AHS was demonstrated in our patient.

CONCLUSIONS

Although AHS is a rare event, it should be suspected in patients who develop unexplained systemic manifestations following exposure to aromatic antiepileptics. The potential of lamotrigine to cause AHS should be remembered when this drug is used in subjects who have developed AHS on exposure to phenobarbital and other first-line antiepileptic agents.