Is coughing up phlegm after each nucleic acid test due to an allergy to the throat swab?
Dec 10, 2025
Source: Cainiu Health
Dr. Liu Wenmin
Introduction
During throat swab collection, the swab may rub against the pharyngeal mucosa, causing mild irritation and increased mucosal secretions, which can lead to coughing with sputum. This condition is usually temporary and resolves spontaneously within 1–2 days without other discomfort. However, if coughing with sputum is accompanied by symptoms such as sore throat, redness, swelling, or itching, it may indicate an allergic reaction to the swab material or disinfectant used. Although such cases are uncommon, they require attention.
Generally, coughing with phlegm after nucleic acid testing is usually caused by throat swab irritation rather than an allergic reaction. However, if accompanied by unusual symptoms, it could indicate an allergy. If concerned, it is recommended to consult a healthcare provider in advance. Specific analysis is as follows:
During throat swab sampling, the mucous membrane of the throat is rubbed, causing slight irritation that increases mucosal secretions, leading to coughing up phlegm. This condition is typically brief and resolves on its own within one or two days without other discomfort.
However, if coughing with phlegm is accompanied by symptoms such as redness and swelling of the throat, itching, rashes, or difficulty breathing, it may indicate an allergic reaction to the swab material or disinfectant used during sampling. Although such cases are uncommon, they should be taken seriously to prevent worsening allergic reactions.
If phlegm production persists after sampling or if allergy-related symptoms develop, prompt medical evaluation is advised to determine the cause. When undergoing sampling, inform healthcare staff if you have a sensitive throat, stay relaxed during the procedure, and minimize mucosal irritation.
