Letters

Managing measles

Size of infecting dose may be important

Editor–In describing severe measles one of us (DCM) made the error of linking the severity directly with the state of nutrition of the child when he or she contracted measles.¹ Several studies have since convincingly shown that the state of nutrition is unimportant, although vitamin A deficiency may play some part. The severity of measles was related to the degree of exposure, which was presumably related to the size of the infecting dose.² Analysis of patients' records from a severe outbreak of measles in Copenhagen in the past showed a similar finding.³ Perhaps the size of dose may vary with the nutritional state of the child passing on the infection.

In his editorial Greg Hussey did not mention these findings.⁴ If the case fatality rate and the severity vary by more than 100-fold between west Africa and Europe this should be worthy of further research to identify whether the degree of exposure and the size of the infecting dose are important in other infections. Perhaps people working in veterinary medicine may be able to help.

Should health workers in developing countries advise mothers to keep other, particularly small children, in separate beds (and where possible in separate rooms) from children who may be incubating or in the early stages of measles and possibly other infections? In Guinea-Bissau it was found that the number of people in the bed was a risk factor for childhood mortality (mortality ratio 1.37 (95% confidence interval 1.04 to 1.81)) when factors such as the number of children in the household, maternal education, sex, age, ethnic group, immunisation, presence of a bathroom, and absence of pigs in the household were controlled for.⁵

D C Morley, Emeritus professor of tropical child health,^a P Aaby, Professor ^b

^a Institute of Child Health, London WC1N 1EH, ^b Danish Epidemiology Science Centre, Statens Seruminstitut, 2300 Copenhagen S, Copenhagen, Denmark

1. Morley DC, Woodland M, Martin WJ. Measles in Nigerian children. J Hyg 1963;61:115-34.
2. Aaby P, Bukh J, Lisse IM, da Silva CM. Measles mortality decline: nutrition, age at infection, or exposure? BMJ 1988;296:1225-8.
3. Aaby P. Severe measles in Copenhagen, 1915-1925. Rev Infect Dis 1988;10:452-6. [Medline]
4. Hussey G. Managing measles. BMJ 1997;314:316-7. (1 February.) [Free Full Text]
5. Aaby P, Jensen H, Nilsen N, Alvarenga I, Andersen M, Clauson-Kaas J, et al. Crowding and health in low-income settlements. Case study report, Bissau. Copenhagen: COWI-consult, 1995.

Crystal violet and eye pads should not be recommended

Editor–Evidence based medicine is fine until we realise just how many of the many things that we order for our patients every day are untested and may never be tested. For example, I have two objections to the advice given by Greg Hussey in his editorial on managing measles.¹ Firstly, he recommends using gentian violet (crystal violet) in the mouth. Martindale: the Extra Pharmacopoeia gives a low rating to crystal violet as an antibacterial, and crystal violet can itself cause ulceration in the mouth and oesophagus.² Nor is crystal violet recommended in the British National Formulary.³ Unfortunately, it is cheap and widely available in developing countries. It is painted on anything that looks diseased, especially burns. This prevents proper assessment of what is going on underneath. Probably its sole indication is for candidal infection when more expensive drugs are not available. Chlorhexidine can be made into a simple, colourless mouthwash, but saline or plain water is probably all that is needed. Secondly, Hussey recommends eye pads. I think that ophthalmologists will agree that eye pads wrongly applied and poorly supervised can be much more destructive to the eyes than fresh air. They also waste precious time, bandages, and dressings, and if applied to both eyes they probably frighten the child unnecessarily. With "measles eyes" already at risk of ulceration, eye pads may just finish the job.

Ian Kennedy, Retired mission doctor ^c

^c 5 Pinwood Lane, Exeter EX4 8NQ

1. Hussey G. Managing measles. BMJ 1997;314:316-7. (1 February.)
2. Martindale: the extra pharmacopoeia. London: Royal Pharmaceutical Society of Great Britain, 1996:1192b.
3. British national formulary No 32. London: BMA and Royal Pharmaceutical Society of Great Britain, 1996:492.

Giving paracetamol for fever is unnecessary

Editor–In his editorial Greg Hussey advises giving paracetamol if the temperature exceeds 39°C as one of the basic management principles when patients are admitted with measles.¹ The common understanding of the general public seems to be that when fever gets too high it can cause death. In hospitals this seems to be confirmed, because paracetamol is given when a patient has a fever. I have not, however, seen a publication to support this. This misunderstanding has major implications for general practice. A paper by Kai illustrates this.²

Current understanding is that people die of the underlying illness, not of fever. To support the benefit of fever one can start with the evolutionary argument. If fever was not of value for survival it would not be part of our defence. Research has shown that many immune responses are enhanced by an increase in temperature. Routine antipyretic treatment for fever is generally unnecessary and conceivably harmful.³ It has been suggested that it may prolong illness and increase or prolong viral shedding.⁴

Parents do not need to worry about febrile convulsions, because when they telephone for advice the fever is already established and the episode of a rapid rise in temperature will have passed. Febrile convulsions, understandably, distress parents, but parents can be reassured that convulsions will not cause a disability. Also, the outcome is determined more by the underlying cause than by the seizures themselves.⁵

In conclusion, and in line with the views of Styrt and Sugerman, I would like to see routine antipyretic treatment reassessed and adjusted, depending on whether desired objectives (such as reduction of cardiovascular stress and increase in comfort) are being achieved.³

I think that paracetamol should be taken off the market. In 1994 the national measles and rubella immunisation campaign was instituted to prevent an expected 50 deaths, mainly among secondary school children. Comparison of this number with the annual number of deaths from paracetamol overdose in Britain (200) indicates that paracetamol should be taken off the market as a similar precaution. If this was done to coincide with a national campaign explaining the benefits of fever then it would have a major educational effect on the general public. Consequently, this would reduce the number of consultations in general practice considerably and would probably enhance the health of the nation.

Wouter H Havinga, General practitioner ^d

^d Randwick, Stroud GL6 6JL

1. Hussey G. Managing measles. BMJ 1997;314:316-7. (1 February.)
2. Kai J. What worries parents when their preschool children are acutely ill, and why: a qualitative study. BMJ 1996;313:983-6.
3. Styrt B, Sugerman B. Antipyresis and fever. Arch Intern Med 1990;150:1589-97. [Abstract]
4. Doran T, De Angelis C, Baumgardner R, Mellits D. Acetaminophen; more harm than good for chickenpox? J Pediatr 1989;114:1045-8.
5. Verity C, Ross E, Golding J. Outcome of childhood status epilepticus and lengthy febrile convulsions: findings of national cohort study. BMJ 1993;307:225-8.

Author's reply

Editor–D C Morley and P Aaby highlight the infecting viral dose and crowding as the most important determinants of mortality. My editorial emphasised that severe disease should be expected in children with severe malnutrition, which is recognised to be an important risk factor for severe and fatal diarrhoea or pneumonia.¹ Diarrhoea and pneumonia are the main complications in children with measles. It would be expected that malnutrition may contribute to excess morbidity and mortality related to measles. Hospital based studies have indicated an association (not necessarily a causal one) between severe malnutrition and complications and death in children with measles.³

I agree with Ian Kennedy that the therapeutic benefit of crystal violet in the treatment of mouth ulcers has not been subjected to rigorous scientific evaluation. At a recent meeting on clinical research in the treatment of measles organised by the World Health Organisation, the aetiology and management of mouth ulcers, including the use of crystal violet, was identified as a priority for further study.³ Herpesvirus infection, candida, and other bacteria probably have a role. There is some evidence that crystal violet exhibits activity against skin bacteria and candida and may reduce morbidity in situations where more expensive therapeutic options are not available.⁴ It is preferable to use a 0.25-0.5% concentration of crystal violet to minimise possible side effects. My recommendation about protective eye pads was that a pad should be applied only if there is evidence of vitamin A deficiency such as corneal ulceration. In such instances, if correctly applied, an eye pad will prevent the child from rubbing the eye and preclude further damage to the eye and secondary infection.⁵ An eye pad is certainly not recommended for uncomplicated "measles eyes."

I note Wouter H Havinga's concerns about the use of paracetamol. The management of fever in children in developing counties has been critically evaluated by the World Health Organisation, which has recommended that paracetamol should be used only when the rectal temperature exceeds 39°C. If paracetamol is prescribed parents must be advised about its correct administration to prevent overuse.

Greg Hussey, Associate professor ^e

^e Department of Paediatrics and Child Health, University of Cape Town, Cape Town, South Africa

1. Fonseca W, Kirkwood BR, Victoa CG, Fuchs SR, Flores JA, Misago C. Risk factors for childhood pneumonia among the urban poor in Fortaleza, Brazil: a case-control study. Bull WHO 1996;74:199-208.
2. Lee LA, Dogore R, Redd SC, Dogore E, Metchcock B, Diabate J, et al. Severe illness in African children with diarrhoea: implications for case management strategies. Bull WHO 1995;73:779-85.
3. World Health Organisation. Clinical research on treatment of measles: report of a meeting. Geneva: WHO, 1995.
4. Foster A. Measles, corneal ulceration and childhood blindness. Trop Doct 1988;18:74-8. [Medline]
5. Bakker P, Van Doorne H, Gooskens V, Wieringa NF. Activity of gentian violet and brilliant green against some microorganisms associated with skin infections. Int J Dermatol 1992;31:210-3.