Is Scarlet Fever Contagious?

Scarlet fever is a contagious disease that mostly affects children. It manifests with symptoms such as fever, rash, and redness of the tongue. Continue reading to find out more about it and what's its mode of transmission.
Is Scarlet Fever Contagious?
Samuel Antonio Sánchez Amador

Written and verified by the biologist Samuel Antonio Sánchez Amador.

Last update: 27 May, 2022

Scarlet fever is a contagious acute infectious disease caused by the bacterial species Streptococcus pyogenes. According to scientific studies, this microorganism is one of the most virulent for humans out of the 74 species that make up this genus.

This bacterium causes both suppurative and non-suppurative pathologies in humans, such as pharyngitis, cellulitis, necrotizing fasciitis, and rheumatic fever, among many others. This is why it’s essential to have this pathogen in focus from a clinical viewpoint. Today we’d like to tell you about scarlet fever and its mode of transmission.

About the distribution of scarlet fever

According to epidemiological publications, scarlet fever is a pathology that mainly affects children. Here’s some data to put into perspective the situation of this disease at a global level:

  • Asymptomatic Streptococcus pyogenes infections are present in 3 to 26% of healthy children in any given population
  • Up to 58% of infants with sore throats may have the bacteria
  • S. pyogenes is the streptococcus species most associated with outbreaks and it’s common for these to occur after eating contaminated food
  • There’s been an increase in scarlet fever outbreaks in recent decades, in 2009 there were over 23,000 documented cases in Vietnam

As you can see, although we’re facing a pathology associated with ancient times, it continues to be present in modern society. That’s why it’s useful to know its mechanism of transmission.

The scarlet fever virus.
Streptococci are behind scarlet fever.

Do you know what are the Health Signals You Can Get from Your Tongue

What’s scarlet fever?

As we mentioned above, scarlet fever is a pathology caused by Streptococcus pyogenes serogroup A infection. According to studies, this bacterium can produce exotoxins and superantigens — causing exaggerated responses by the immune system. Thus, its action on the human body covers a wide range of symptoms.

The most common places of bacterial colonization are the mucous surfaces and the skin, to a lesser extent. Portals such as the US National Library of Medicine have a list of symptoms associated with scarlet fever:

  • The infection begins with fever and sore throat
  • There’s a rash with a primary appearance in the neck and chest that then spreads throughout the body
  • Also, there’s swelling of the lymph nodes in the neck
  • Finally, there are secondary symptoms such as body aches, nausea, chills, and redness and swelling of the tongue

Note that the most obvious symptom of this disease is the appearance of the rash. While the first signs appear in the first or second day after infection, the skin rash usually occurs after 3 to 5 days and lasts more than a week.

Is scarlet fever contagious?

According to professional pediatric organizations such as Kidshealth, scarlet fever is highly contagious. Both direct contact with the affected surface (in the case of patients with impetigo, another manifestation caused by this bacterium) and inhalation of microparticles (coughing and sneezing) from a sick person can spread the infection to a healthy patient.

In addition, note that this microorganism survives on inanimate surfaces for up to four weeks. Therefore, touching materials or food that have been in contact with a sick person and then putting your hands in your mouth is a potential danger.

Official agencies, such as the Centers for Disease Control and Prevention (CDC), warn that one of the most common causes of scarlet fever outbreaks is poor food handling. However, experts don’t believe pets or toys can transmit the bacteria, as long as disinfection is adequate.

Period of infection

The contagious period lasts as long as the symptoms do. In spite of this, it’s a mild infection that easily remits with the application of antibiotics. Note that the patient is no longer contagious after 48 hours of treatment.

How to prevent the spread of this condition

A pair of hands with a rash.
Scarlet fever is frequent in the pediatric age, as another exanthematic disease.

As you can see, scarlet fever is a mild but highly contagious pathology transmitted by unsanitary surfaces or by micro-particles of saliva from sick people. Thus, proper hygiene habits are the first barrier of defense against it. Here are some guidelines to follow in order to prevent it:

  • Cover your nose and mouth with a tissue when you sneeze
  • Wash your hands frequently with soap and water for at least 20 seconds
  • Restrict the affected person’s utensils to their use only
  • Follow a strict food and surface sanitation protocol in places where epidemiological outbreaks occur

Scarlet fever and its spread

This is a highly contagious infection caused by a microorganism that’s widespread in the general population. Even so, it’s a mild infection that, with antibiotic treatment, goes away in a few days.

Even though a patient may present complications, such as pneumonia or sinus infections, these aren’t common at all. However, you must consult a doctor whenever there’s a generalized rash associated with a feverish process.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.