Re: Photophobia and a painful rash
Herewith I would like to comment on the interesting case review on herpes zoster ophthalmicus (HZO) by Andrew Malem.(1)
First, HZO can indeed only develop after a patient has been previously infected by the varicella zoster virus (VZV). A negative answer to the question whether the patient ever had chickenpox does, however, have a low predictive value for the absence of the virus. Holmes analysed 12 cross-sectional studies, conducted in the period 1996–2002, on the association between a history of chickenpox and the presence of VZV antibodies.(2) In adults, a reported positive history of chickenpox correlated highly with the presence of protective VZV titres (positive predictive value > 95%), while a reported negative history did not (negative predictive value < 35%). These findings indicate that a positive history of chickenpox is a reliable marker of disease, while a negative history does not predict a lack of previous infection. In other words, when a patient with a painful rash cannot remember having had chickenpox, HZO cannot be ruled out.
Second, chickenpox infection in newborn children is not always severe. However, serious cases do occur when the mother develops the disease in the perinatal period 5 days before to 2 days after delivery as the child will have been hematogenously infected with the virus during this period.(3) If an immunocompetent newborn child is infected non-hematogenously – i.e. by someone else with chickenpox or shingles – the chickenpox will usually develop without complications, regardless of the serological status of the mother. Nevertheless, the incidence of fatal chickenpox in children less than 1 year old is 4 times higher than it is in older children.(4)
Finally, the Hutchinson’s sign indeed predicts subsequent ocular inflammation in patients with HZO. In his paper, Malem focuses attention on the tip of the nose because of the external branch of the nasociliary nerve. The dermatome of the nasociliary nerve is, however, more extensive and includes the skin at the inner corner of the eye and the root and side of the nose (see figure).(5, 6) Therefore, even if blisters do not form on the tip of the nose, the eye can become involved in the inflammation.
1. Malem A. Photophobia and a painful rash. BMJ 2016;353:i3221.
2. Holmes CN. Predictive value of a history of varicella infection. Can Fam Physician 2005;51:60-5.
3. Meyers JD. Congenital varicella in term infants: risk reconsidered. J Infect Dis 1974;129:215-7.
4. Preblud SR, Bregman DJ, Vernon LL. Deaths from varicella in infants. Pediatr Infect Dis 1985;4:503-7.
5. Zaal MJ, Völker-Dieben HJ, D'Amaro J. Prognostic value of Hutchinson's sign in acute herpes zoster ophthalmicus. Graefe's Arch Clin Exp Ophthalmol 2003;241:187-91.
6. Opstelten W, Zaal MJ. Managing ophthalmic herpes zoster in primary care. BMJ 2005;331:147-51.
Competing interests: No competing interests