The Little Ones' Cold

When a child catches a cold, parents or guardians naturally panic when symptoms like fever, diarrhea, or persistent coughing and vomiting occur. Colds are typically caused by some form of pathogen. I emphasize "typically" because there are still illnesses like Kawasaki disease with cold-like symptoms whose causes remain unknown. Here, I'll discuss children's colds caused by bacterial or viral infections season by season, and briefly touch upon Kawasaki disease at the end.

Now, when both children and adults experience cold-like symptoms such as fever, headache, sore throat, cough, abdominal pain, or diarrhea, do you know which is more common as the cause: bacteria or viruses? The answer is viruses. Antibiotics only work against bacteria, so they're rarely prescribed for most children with colds. However, if a cold persists and leads to complications like ear infections or pneumonia, or if the child has an underlying condition, bacterial infection may need to be considered, warranting the prescription of antibiotics.

Sometimes, there's a request to prescribe antibiotics "just in case" there's a possibility of bacterial infection, even though viral causes are more likely. However, this isn't typically done due to public health concerns. Unnecessary antibiotic use leads to the emergence of antibiotic-resistant bacteria, limiting future treatment options and potentially leading to life-threatening infections. In fact, inappropriate antibiotic use has become a societal issue, leading to challenges in medical treatment. On a larger scale, antibiotics, after serving their purpose in the body, are excreted into the environment, where they disrupt delicate ecological balances in rivers and streams, altering bacterial communities and accelerating the emergence of resistant strains.

From another perspective, in infectious mononucleosis, a viral infection common among adolescents and young adults, taking certain antibiotics can cause a widespread rash, so caution is needed when considering antibiotic use for early cold symptoms.

In any case, the casual use of antibiotics should be approached with caution from various perspectives.

Guidelines for bringing your child to a medical facility

Now, back to the topic. If your child catches a cold, dress them warmly if they feel cold, or remove a layer if they feel hot. If they find relief from ice packs or cooling sheets on their forehead, feel free to use them. As long as you create a quiet, restful environment, children will typically recover quickly. If your child doesn't want to eat, there's no need to force them, but if they have a high fever, vomiting, or diarrhea, they may become dehydrated, so offer small amounts of fluids at intervals. As long as they're getting enough fluids, they should be fine, but if they become lethargic, produce less urine, don't respond to stimuli, have rapid breathing and appear to be struggling to breathe, it's essential to seek medical attention.

Now, let's delve into the specific causes of children's colds season by season.

Winter

Winter is the season when people are most susceptible to catching colds due to sudden changes in temperature and the tendency for viruses to spread in dry air.

Influenza

When it comes to winter colds, seasonal influenza is the most well-known. It is caused by infection with the influenza virus. Symptoms include a sudden high fever, extreme fatigue, sore throat, cough, joint pain, and muscle aches. The incubation period (the time from infection to the onset of symptoms) is typically around 2 days, and in most cases, it resolves within a week without any specific treatment. However, in infants, young children, or those with underlying health conditions, complications such as pneumonia or exacerbation of existing conditions may occur, requiring careful attention. There are limited types of recommended fever-reducing medications for children. Additionally, antiviral medications specific to the influenza virus may be used to shorten the duration of symptoms. According to the School Health and Safety Act in Japan, children should stay home from school or daycare for at least 5 days after symptom onset (6 days from onset) and for 2 days after fever subsides (3 days for infants). The presence of influenza can be confirmed through antigen testing of nasal and throat swabs, which provides rapid results. Prevention is crucial, and flu vaccination campaigns typically begin in the fall. Vaccination for the entire family, especially for households with children with underlying conditions, elderly individuals, or those facing upcoming exams, can significantly reduce the severity of symptoms if infection occurs.

COVID-19

While the novel coronavirus circulates almost year-round, it tends to be more prevalent in the dry winter air. The virus undergoes slight changes with each outbreak and is recognized as a virus that can cause pneumonia. Several antiviral drugs have been developed for its treatment. Symptoms include fever, cough, phlegm, fatigue, joint pain, headache, and sore throat. The presence of COVID-19 can be confirmed through antigen testing of nasal and throat swabs, which provides rapid results. Since April 2023, COVID-19 has been classified as a Category 5 infectious disease under the Infectious Diseases Control Law in Japan. Similar to influenza, children should stay home from school or daycare for at least 5 days after symptom onset (6 days from onset) and for 2 days after fever subsides (3 days for infants). Adults are generally advised to refrain from going out for 7 days after symptom onset, but there is no legal basis for this, so it's up to individual discretion. Regular vaccination updates and guidelines are provided by the Ministry of Health, Labour, and Welfare, as recommendations for COVID-19 vaccination may change. Vaccination is recommended for children with underlying conditions, and the recommended age for vaccination may vary by product. According to the revised guidelines of the Japanese Pediatric Society in April 2024, vaccination is generally recommended for all children aged 6 months and older.

Norovirus

Norovirus is a common cause of infectious gastroenteritis, particularly during the winter months. It spreads orally through contaminated hands, food, etc., replicates in the human intestine, and causes symptoms such as vomiting, diarrhea, and abdominal pain. Healthy individuals typically recover from mild symptoms, but children and the elderly may experience severe complications. Symptoms usually last for 1-2 days before resolving. "Norovirus antigen testing" detects the presence of norovirus in feces using a testing kit, and it is covered by health insurance in Japan for individuals under 3 years old or over 65 years old, among others, allowing for testing in suspected cases.

Spring

The gradually warming season also marks the onset of pollen allergies, commonly known as hay fever. During this time, cold-like symptoms in young children may actually be due to allergies to pollen, making it essential to be vigilant. Since the initial symptoms of hay fever can be easily mistaken for a cold, it's important to pay attention. However, persistent runny noses in young children can lead to conditions like otitis media or sinusitis, so if a child starts to develop a fever and becomes cranky, it's advisable to seek medical attention even if it initially seems like just sneezing and a runny nose. While not exclusive to spring, it's also important to be aware of infections such as rotavirus and streptococcal infections.

Rotavirus

Rotavirus causes acute gastroenteritis in infants and young children and is characterized by symptoms such as watery diarrhea, nausea, vomiting, fever, and abdominal pain. It's said that almost all children are infected with rotavirus by the age of 5, so there's no need to be overly fearful. However, dehydration can worsen if diarrhea and vomiting persist, so if a child becomes less responsive or appears lethargic, seek medical attention. Babies are recommended to receive routine vaccination against rotavirus, with the first dose administered between 8 and 14 weeks of age (can be given as early as 6 weeks). Vaccination reduces the risk of severe gastroenteritis. However, it's not recommended to receive the first dose after 15 weeks of age if it has been missed, so caution is needed in this regard.

Streptococcal Infections (Year-round)

Spring marks the beginning of the school year in Japan, and it's a season when young children are prone to falling ill as they enter group settings for the first time. Some children may also first become aware of food allergies during school life. Amidst this, one of the pathogens that can cause cold-like symptoms with sore throat, fever, and sometimes rash is Streptococcus. Streptococcal infections often cause swelling of the lymph nodes in the neck, which can be painful to touch. While the throat may feel sore and children may refuse to eat, coughing is not typically present. As mentioned earlier, antibiotics are ineffective against colds, but streptococcal infections are an exception as they are bacterial infections. While the skin on fingertips may peel as cold symptoms improve, this is a natural healing process. However, if a child's urine output decreases, becomes cloudy, or contains blood, it's advisable to seek medical attention for urine testing.

Summer

Pharyngoconjunctival Fever

Pharyngoconjunctival fever, also known as pool fever, is a viral infection in children characterized by fever, sore throat, eye redness, and eye discharge. It's caused by infection with adenovirus and typically begins to increase around June, reaching its peak in July and August. Infections can occur through contact in swimming pools or shared towels, so it's important to avoid sharing towels within families until symptoms resolve. Adenovirus is resistant to alcohol disinfection, so frequent handwashing with soap and water is effective for prevention. Diagnosis is mostly based on symptoms, but adenovirus antigen can also be detected from nasal and throat swabs. There's no specific treatment, and symptomatic therapy is provided according to the symptoms. Under the School Safety Act in Japan, children should refrain from attending school until 2 days after symptoms have resolved.

Herpangina

Herpangina, a representative summer cold, is characterized by fever and small blister-like eruptions in the throat that cause pain. It's caused by infection with enteroviruses such as Coxsackievirus and typically begins to spread from around May, peaking in June and July. Most cases occur in children under 4 years old. Due to throat pain, children may temporarily refuse to eat or drink, so it's necessary to alleviate symptoms with appropriate pain relief. While herpangina is not considered a contagious disease to be prevented at schools, dehydration should be monitored, and affected children should be allowed to rest at home when fever and loss of appetite are severe. Medical attention is recommended if a child appears lethargic.

Hand, Foot, and Mouth Disease

Hand, foot, and mouth disease, caused by infection with Coxsackievirus or enterovirus, is a viral infection characterized by blister-like eruptions in the mouth, hands, and feet, primarily peaking in summer. It mostly occurs in children under 5 years old. Characteristically, eruptions also appear on the palms and soles, and while fever may occur, it's usually not very high. Symptoms typically resolve within a few days. Additionally, it's been reported that children may temporarily lose their fingernails within a month after the eruptions disappear, but this is also a natural healing process. Hand, foot, and mouth disease is not classified as a contagious disease to be prevented at schools, but medical attention should be sought if symptoms such as high fever, vomiting, or lethargy are observed.

Autumn

We've been discussing seasonal colds, starting from winter, then moving through spring and summer, and now we arrive at utumn. Autumn is a season of harvest, with many trees bearing fruit. Some trees also release pollen during this time, so if you experience symptoms like a runny nose, sneezing, or itchy eyes, it might be worth considering hay fever. One of the representative cold viruses that spreads from the end of summer through autumn is the Respiratory Syncytial Virus (RSV), so let's delve into that.

Respiratory Syncytial Virus (RSV)

RSV is a well-known virus that infects the respiratory tract (airways, bronchi, lungs), and it's estimated that over half of infants are infected by age 1, with nearly 100% infected by age 2. Symptoms range from mild cold symptoms such as fever and runny nose to severe pneumonia. Infants under 6 months of age are at risk of severe illness if infected with RSV, so caution is necessary. Similarly, children with underlying conditions at high risk of complications from infection (such as premature birth, cardiac or pulmonary conditions in children under 24 months of age, neurological or muscular disorders, or immunodeficiency) also require attention. Some newborns and infants are eligible for insurance-covered administration of antibody preparations against RSV. Administering injections during the early stages of an RSV outbreak and continuing monthly injections throughout the outbreak can help prevent severe illness in such children.

We've now covered infectious diseases to be aware of in the order of winter, spring, summer, and autumn. How does it look? Finally, let's discuss two important infections that aren't seasonal, as well as Kawasaki disease, which can be difficult to distinguish from a cold but is troublesome if overlooked, to conclude this discussion.

Mycoplasma Pneumonia

Mycoplasma pneumonia is a pathogen that falls between viruses and bacteria and is common in children and adolescents aged 5 to 15, although the incidence in younger children, including infants, has been increasing. Persistent dry cough is a characteristic symptom. It's not a legally notifiable infectious disease. It tends to recur in cycles of about four years. Specific antibiotics are effective for treatment, so proper diagnosis can help control the infection.

Roseola Infantum

Roseola infantum is a viral infection characterized by sudden high fever and rash on the body before and after fever reduction in infants, caused by Human Herpesvirus 6 or 7. Despite the high fever, children usually remain active, but they may become irritable once the rash appears after fever reduction. Febrile seizures may occur in the early stages of fever, causing panic among parents or caregivers. However, recovery usually occurs without problems afterward, so there's no need to worry excessively.

Kawasaki Disease

Kawasaki disease is an unexplained illness first reported by Dr. Tomisaku Kawasaki, a pediatrician, in 1967. It mainly affects infants under 4 years old and causes inflammation in the blood vessels throughout the body, resulting in various symptoms. Diagnosis of Kawasaki disease is made when five or more of the six symptoms, including high fever, bilateral conjunctival congestion (red eyes), strawberry-like tongue with red lips, rash on the body, swelling of the hands and feet, and swelling of the lymph nodes in the neck, are present. Redness and swelling at the site of BCG injection in young children are also characteristic symptoms. The most concerning aspect of Kawasaki disease is the development of aneurysms in the coronary arteries, which supply blood to the heart, particularly in untreated cases. Hospitalization is necessary once diagnosed, and children with Kawasaki disease are initially treated with intravenous immunoglobulin and aspirin to prevent blood clotting.

hildren can catch colds for various reasons. Since no child is immune to catching a cold, there's no need to worry excessively, but if any concerning symptoms persist, I recommend seeking medical attention. I hope this article provides some peace of mind to mothers, fathers, and caregivers.