The Hong Kong Centre for Health Protection (CHP) of the Department of Health are appealing to parents, schools/institutions and healthcare professionals for heightened vigilance against scarlet fever (SF) as its activity has been increasing in the past few weeks.

This patient revealed a scarlet fever rash on the volar surface of the forearm due to group A Streptococcus bacteria Image/CDC
This patient revealed a scarlet fever rash on the volar surface of the forearm due to group A Streptococcus bacteria

According to the CHP’s surveillance data, the weekly number of SF cases increased from 37 in the week of October 22 to 61 and 66 in the two subsequent weeks. Regarding SF outbreaks in schools/institutions, as of November 11, three affecting 10 pupils/children were recorded in November.

“While SF has occurred throughout the year locally, a seasonal pattern for SF in Hong Kong with higher activity was observed from May to June and from November to March in the past few years. Based on the past epidemiological pattern, we expect that the SF activity will remain at a higher level in the coming few months. Parents have to take extra care of their children in maintaining strict personal, hand and environmental hygiene,” a spokesman for the CHP said.

A total of 1,682 SF cases were reported to the CHP in the first 10 months of 2017, representing a marked increase from the figures for the same period in 2016 (1,062 cases) and 2015 (948 cases). The epidemiological and clinical features of the cases recorded in 2017 were largely similar to those in previous years.

Among the 1,682 SF cases reported this year, they comprise 977 males and 705 females aged from 2 months to 43 years (median: 5 years), nearly all of which (1,607, 95.5 per cent) were under 10 years. Most presented with mild illnesses. Among them, 611 cases (36.3 per cent) required hospitalization. While one severe case reported in March required admission to an intensive care unit, no deaths have been recorded so far.

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Scarlet fever is a bacterial illness that usually follows a sore throat or a skin infection (impetigo) caused by Group A streptococcus bacteria.

The characteristic symptom of scarlet fever is a widespread, fine pink-red rash that feels like sandpaper to touch. It may start in one area, but soon spreads to many parts of the body, such as the ears, neck and chest. The rash may be itchy.

Other symptoms include a high temperature, a flushed face and a red, swollen tongue.

Symptoms of scarlet fever usually develop two to five days after infection, although you will be contagious before showing signs of the illness.

Scarlet fever is extremely contagious and can be caught by: breathing in bacteria in airborne droplets from an infected person’s coughs and sneezes; touching the skin of a person with a streptococcal skin infection and sharing contaminated towels, baths, clothes or bed linen. It can also be caught from carriers – people who have the bacteria in their throat or on their skin but do not show any symptoms.

Scarlet fever is mainly a childhood disease and is most common between the ages of 2 and 8 years. It was once a very dangerous infection, but although much less serious now, complications can arise, particularly in those who remain untreated. There is currently no vaccine for scarlet fever.