The origin of the condition
- The common cold is an infection of the upper respiratory system caused by a virus (there are more than 200 types of viruses capable of causing it). It is easily transmitted from person to person through airborne droplets or by touching contaminated surfaces.
- Allergic rhinitis is not an infection, but rather an exaggerated response of the immune system to environmental substances that it mistakenly identifies as threats (known as allergens). Common triggers include dust, pollen, mold, pet dander, and dust mites.
The duration of the symptoms
- A common cold follows a self-limiting course. Symptoms typically develop gradually and disappear completely within 7 to 10 days.
- Allergic rhinitis persists for as long as the person remains exposed to the allergen. It can last for weeks or months, or occur consistently during certain times of the year (seasonally), such as in the spring or autumn.
The consistency of the mucus
Paying attention to the characteristics of nasal discharge provides key clues. In the case of a common cold, the mucus typically starts out clear and watery, but as days pass, it becomes thick, cloudy, and takes on a yellowish or greenish hue due to the immune response against the virus. In contrast, the mucus associated with allergic rhinitis almost always remains thin, clear, and runny.
The hallmark: itching
Intense itching is the defining characteristic of an allergy. If, in addition to nasal congestion, you experience a constant urge to scratch your nose, throat, palate, or eyes—often accompanied by watery, red eyes—it is highly likely that the diagnosis is allergic rhinitis rather than a common cold.
When is it necessary to consult a specialist?
Medical or otolaryngological attention should be sought when symptoms significantly affect sleep quality, school or work performance, or if complications arise—such as severe ear pain, intense facial pressure, or persistent difficulty breathing.
An accurate diagnosis will prevent the unnecessary use of antibiotics (which are ineffective against viruses or allergies) and allow for the implementation of targeted treatments, such as antihistamines, nasal sprays recommended by a healthcare professional, or immunotherapy.
Fountain:
- Allergic rhinitis or the common cold? How to learn to distinguish between them in a practical way. (2026). Otorhinolaryngology and Respiratory Health Section. Produced in collaboration with the editorial-assistance language model Gemini (Google, 2026).
