Phenobarbital is still one of the most commonly used medical treatments for different types of seizures. It has numerous different side-effects. Antiepileptic hypersensitivity syndrome (AHS) is a rare and potentially life-threatening adverse reaction to aromatic anticonvulsants such as phenobarbital. Its characteristic features are fever, rash, and lymphadenopathy with different severity of hematologic abnormalities. This case report presents a 26-month-old girl that developed fever, disseminated maculopapular rash, petechiae and thrombocytopenia two weeks after the initiation of phenobarbital prescribed for febrile seizure prophylaxis. The patient was admitted in our center with the impression of hypersensitivity syndrome, so phenobarbital was discontinued and her treatment was resumed with methylprednisolone and intravenous immunoglobulin. After a few days, all symptoms improved and the platelet count was normalized. Thrombocytopenia is a rare complication of hypersensitivity syndrome to phenobarbital in children. Paying attention to this point can prevent the life-threatening adverse effects of this highly consumed medicine.

Olanzapine has become one of the most commonly prescribed atypical antipsychotic drugs in Iran. Hypersensitivity syndrome is a rare side effect of this drug. In this article, a case of this syndrome is reported. A 54 year old man, who was a known case of schizophrenia, was under treatment with olanzapine. Five days after beginning the treatment, a drug-skin-reaction appeared and on day 10, he showed Guillain-Barre syndrome. The patient was treated with plasma exchange and improved in a few weeks.

Drug-induced hypersensitivity syndrome (DHS), alsonameddrug rash with Eosinophilia and systemic symptoms (DRESS) is a potentially dangerous side effect of some drugs, especially antiepileptic drugs (AEDs) such as phenobarbital, phenytoin, carbamazepine, lamotrigine, primidone, etc. It can also be caused by other drugs, such as sulfonamides and captopril. Diagnosis of DHS may be difficult because of the variety of clinical and laboratory abnormalities and manifestations and because the syndrome may mimic infectious or collagen vascular disorders. Management includes immediate withdrawal of the culprit drug, supportive care and systemic steroids or Immunoglobulins (IVIG). Here, we briefly reviewed the literature, followed by a case report that had all of the criteria of DRESS without eosinophilia.