A 2½-year-old boy presented to us with high grade fever and cough for a day. There was no rash or any other obvious focus of infection. A diagnosis of viral fever was considered. As there was recent contact with a H1N1 influenza patient in the family, a possibility of H1N1 infection was considered in this young child and oseltamivir was administered at a dose of 30 mg twice daily for 5 days. Though there was infrequent cough, the fever abruptly abated 48 hours after initiation of oseltamivir. On the fourth day of illness, skin lesions typical of Hand, foot and mouth disease (HFMD) were noted over limbs, palms and soles. However, the lesions healed quickly and desquamated in 2 days. This child probably acquired HFMD from other children in his playschool. Incidentally, the oseltamivir he received for possible H1N1 infection resulted in earlier cessation of fever and resolution of skin lesions. Though HFMD is usually self-limiting, fever and skin lesions for one or two weeks may be distressing for both children and their parents. If a safe antiviral drug can shorten the duration and intensity of the illness, it may become a treatment option. However, this clinical observation is very preliminary and proper research evidence is needed to document any such benefit.

Oseltamivir phosphate is an oral prodrug which undergoes hydrolysis by hepatic esterases to form active oseltamivir carboxylate which acts by selective inhibition of influenza A and B viral neuraminidase. A lipophilic side chain of the active drug binds to the virus enzyme, blocking its ability to cleave sialic acid residues on the surface of the infected cell resulting in an inability to release progeny virions [1]. Usage of sialic acid is a common feature of at least three different viruses with pandemic potential: Coxsackie Virus A24, Entero Virus 70, and influenza A virus [2]. This sialic acid link could be a common pathway by which oseltamivir helps in HFMD.

1. McNicholl IR, McNicholl JJ. Neuraminidase inhibitors: Zanamivir and oseltamivir. Ann Pharmacother. 2001;35:57-70.

2. Nilsson EC, Jamshidi F, Johansson SM, Oberste MS, Arnberg N. Sialic acid is a cellular receptor for coxsackievirus A24 variant, an emerging virus with pandemic potential. J Virol. 2008;82:3061-8.