Drug-induced hypersensitivity syndrome with human herpesvirus-6 reactivation.

A 45-year-old man, on carbamazepine for the past 3 months, was referred as a case of atypical measles. On examination, he had high-grade fever, generalized itchy rash, cough, vomiting and jaundice. A provisional diagnosis of drug hypersensitivity syndrome to carbamazepine was made with a differential diagnosis of viral exanthema with systemic complications. Laboratory investigations revealed leukocytosis with eosnophilia and elevated liver enzymes. Real-time multiplex polymerase chain reaction (PCR) on throat swab and blood was suggestive of human herpesvirus-6 (HHV-6). Measles was ruled out by PCR and serology. The diagnosis of drug-induced hypersensitivity syndrome (DIHS) was confirmed, which could explain all the features manifested by the patient. HHV-6 infects almost all humans by age 2 years. It infects and replicates in CD4 T lymphocytes and establishes latency in human peripheral blood monocytes or macrophages and early bone marrow progenitors. In DIHS, allergic reaction to the causative drug stimulates T cells, which leads to reactivation of the herpesvirus genome. DIHS is treated by withdrawal of the culprit drug and administration of systemic steroids. Our patient responded well to steroids and HHV-6 was negative on repeat real-time multiplex PCR at the end of treatment.

Association of HLA-B*1502 allele and carbamazepine-induced Stevens-Johnson syndrome among Indians.

BACKGROUND: Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis are severe cutaneous reactions caused by certain drugs, including antiepileptic carbamazepine. A strong association has been reported between human leucocyte antigen (HLA)-B*1502 and carbamazepine-induced SJS in Han Chinese patients. European studies suggested that HLA-B*1502 is not a universal marker but is ethnicity-specific for Asians. AIM: To study the association between HLA-B*1502 and carbamazepine-induced SJS in Indian patients. METHODS: Eight individuals who fulfilled the diagnostic criteria of SJS induced by carbamazepine were identified and HLA-B molecular typing was performed. HLA-B genotyping was carried out by polymerase chain reaction using sequence-specific primers. RESULTS: Out of eight patients studied for genotype, six patients were found to have the HLA-B*1502 allele. CONCLUSION: This study suggests an association between HLA-B*1502 and carbamazepine-induced SJS in Indian patients.

Eosinophilic leukemoid reaction associated with carbamazepine hypersensitivity.

Carbamazepine is widely used in the treatment of epilepsy, neuralgic pain, and bipolar affective disorders. Several adverse drug reactions have been described during the course of carbamazepine administration, including exanthemata and hematological reactions. Carbamazepine is one of the common drugs that have been implicated in the etiology of drug hypersensitivity syndrome. A 50-year-old male presented with generalized erythroderma following 10 weeks of ingestion of carbamazepine 200 mg daily for idiopathic epilepsy. His systemic examination was within normal limits. Blood counts revealed marked eosinophilia of 52% (absolute eosinophil count of 10,400 per mm3). Bone marrow aspiration revealed a moderate increase in the eosinophilic series with cells showing normal morphology. The eosinophil counts returned to normal after 2 weeks of oral prednisolone therapy. This case is reported because of its rarity in the Indian medical literature.

Carbamazepine--the commonest cause of toxic epidermal necrolysis and Stevens-Johnson syndrome: a study of 7 years.

BACKGROUND: Toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS) are a group of severe life threatening drug reactions. The drugs commonly implicated as the cause of these drug reactions vary depending on host factors and the prescription pattern of drugs in that particular area. AIM: The aim of the study was to find the drugs implicated as the cause of SJS/TEN in the patients admitted in the dermatology ward at the Medical College, Thrissur and to find the clinical outcome. METHODS: It was a retrospective study of 7 years from 1997 to 2004. The case records of all patients with a clinical diagnosis of TEN or SJS were studied in detail regarding the drugs implicated as the cause, the management and the clinical outcome. RESULTS: During the study period, 41 patients in the age group ranging from 12 to 72 years were treated as inpatients, of which 20 were males and 21 were females. The commonest drug implicated as the cause of SJS/TEN was carbamazepine (44%). The indication for carbamazepine was control of pain in more than 50% of the cases. Presence of a major systemic disease before the onset of SJS/TEN was associated with a bad prognosis. CONCLUSION: The increased use of carbamazepine, especially for control of pain, may be the reason for the increased incidence of SJS/TEN due to the same drug. Awareness about the drugs implicated in life threatening drug reactions will help physicians in preventing them by judicious use of the drugs.