What is a cold?

The common cold, officially known as “cold syndrome” or “influenza,” generally refers to a collection of symptoms such as sneezing, runny nose, nasal congestion, sore throat, cough, phlegm, and fever. Colds are often caused by viral infections, with over 200 known types of viruses. It is a different disease from the flu that is prevalent in winter, and unlike the flu, whose symptoms are sudden and affect the entire body, the symptoms of a cold are relatively gradual and mild, and are localized to areas such as the throat and nose. 

最后更新：2026年3月。由CLINIC TEN SHIBUYA医疗团队监修。

Cold symptoms and their characteristics

Cold symptoms vary. The main ones are nasal symptoms such as runny nose, stuffy nose, and sneezing, as well as throat symptoms such as sore throat, cough, and phlegm. Sometimes they are accompanied by systemic symptoms such as fever, general fatigue, headache, joint pain, and digestive symptoms. Because there are no specific symptoms that indicate a cold, some people may think they have a cold but end up with a different illness. If symptoms persist for more than a week, it is recommended that you see a doctor.

Cold treatment and precautions

Generally, medicines are prescribed to alleviate symptoms rather than to kill the underlying virus. For example, fever-reducing medicines are used for fever, and medicines to suppress coughs and phlegm are used for respiratory symptoms, as well as medicines that open the airways to make breathing easier.

Some people want to use or be prescribed antibiotics, but antibiotics are not effective against the viruses that cause colds. Therefore, taking antibiotics will have no effect. However, a cold can sometimes cause bacterial infection, leading to otitis media or sinusitis. In this case, antibiotics may be necessary to fight the causative bacteria. If you have persistent ear or nose symptoms, be sure to fill out the questionnaire before your appointment or tell your doctor during your appointment.

According to a 2019 survey by the Health and Global Policy Institute, Japan…

What happens if the cold lasts for a long time?

If a cold worsens, it can lead to more serious illnesses such as bronchitis, pneumonia, otitis media, sinusitis, etc. Pneumonia in particular is common among the elderly and children, and can be life-threatening, so caution is required.

Many complications occur through a process known as secondary infection, in which new bacteria or viruses that have attached themselves to the mucous membrane infect cells in the body whose resistance has been weakened by the cold. If your high fever persists for more than five days or your cough becomes severe, you should see a medical institution as soon as possible. CLINIC TEN asks that you consult an online medical consultation in these cases.

summary

• Colds are mainly caused by viral infections and symptoms include sneezing, runny nose, nasal congestion, sore throat, cough, phlegm, and fever.
• Treatment is basically symptomatic, but secondary infections can cause the condition to become severe, in which case antibiotics or other medications are used.

Doctor’s comment

The so-called “cold” occurs when a virus spreads throughout the body, causing symptoms in various parts of the body, such as the nose, throat, or fever.

These symptoms are collectively called a cold, and similar symptoms occur with influenza and COVID-19. This makes it very difficult to distinguish between the two illnesses, but regardless of the cause, if the symptoms are mild, it is sufficient to treat them with only fever-reducing and analgesic medications to suppress the symptoms.

Antibiotics do not attack viruses, so their use will be ineffective.

References

Krammer F, Smith GJD, Fouchier RAM, et al. Influenza. Nat Rev Dis Primers. 2018;4(1):3. Published 2018 Jun 28. doi:10.1038/s41572-018-0002-y
Brankston G, Gitterman L, Hirji Z, Lemieux C, Gardam M. Transmission of influenza A in human beings. Lancet Infect Dis. 2007;7(4):257-265. doi:10.1016/S1473-3099(07)70029-4
インフルエンザQ&A｜厚生労働省

常见问题

感冒和流感有什么区别？

感冒通常缓慢起病，主要症状为流鼻涕、打喷嚏和轻微咳嗽。流感（流行性感冒）的特点是突然高烧（38°C以上）、严重肌肉酸痛和全身乏力。在日本的诊所可以通过快速检测来区分。

在日本哪里可以买到感冒药？

在日本的药妆店可以购买多种综合感冒药。Pabron（パブロン）、Lulu（ルル）等是日本常见的感冒药品牌。向药剂师描述症状可以获得合适的推荐。

感冒一般要多久才能好？

普通感冒通常持续7～10天。如果症状超过10天仍未好转或加重，可能出现了鼻窦炎等并发症，请就医检查。