Benzalkonium Chloride Intoxication Mimicking Herpes Zoster Encephalitis

Encephalitis is an acute infl ammation of the meninges and cerebral tissue. Although the specifi c etiological agent is not identifi ed in many instances, clinical and research experience indicate that viruses are the responsible pathogens for most infections. Enteroviruses cause more than 80% of all cases (1, 2). The other frequent viral causes are arboviruses and Herpes viruses. Herpes simplex encephalitis is very rare in healthy children younger than 10 years of age, whereas encephalitis, ranging from mild to severe, either accompanying or following Herpes zoster, is not uncommon (3, 4). However, a variety of non-infectious disorders may also be associated with CNS infl ammation and have manifestations similar to those associated with viral meningoencephalitis. Some of these disorders include malignancy, collagen vascular diseases, intracranial hemorrhage and exposure to certain drugs or toxins (1-3). However, in this case report we describe vesicular exanthema and encephalopathy mimicking a Herpes simplex virus encephalitis as a result of benzalkonium chloride (BAC) application to the scalp to treat pediculosis capitis.