Why does a stubborn cough, especially that annoying throat itch, linger even after recovering from COVID? It often strikes suddenly in the quiet of night or when speaking, causing racking coughs, chest tightness, and even affecting sleep and work. What can be done?
What Causes Persistent Throat Itch and Cough After COVID?
Dr. Que Poh Yuen Albert, TCM expert at Singapore Gong Fang Tang TCM Department, explains that this lingering post-COVID cough often stems from lung yin consumption and lingering pathogens. During a COVID-19 infection, high fever, qi depletion, and fluid damage are common pathological features. Especially in the recovery phase, although the main pathogenic force has subsided, "sequelae" often remain:
Dryness Pathogen Damages the Lungs, Lung Yin Deficiency: Fever, sweating, and rapid breathing consume large amounts of lung fluids. The lungs prefer moisture and dislike dryness. With insufficient yin fluids, the lungs lose nourishment, leading to a dry, itchy throat, triggering bouts of dry cough (with little or no phlegm), and a tendency for hoarseness.
Residual Heat Unresolved, Deficient Fire Flaring Upward: Some residual heat (fire) pathogens fail to be completely cleared, lingering in the lung system. Deficient fire flares upward, scorching the throat, worsening dryness, itchiness, and pain, stimulating coughing.
Lung Collaterals Disharmony, Airway Sensitivity: After the epidemic toxin invasion, the lung's functions of diffusion and depuration become dysregulated. Airway mucosal repair is incomplete, becoming hypersensitive. Slight stimulation (like cold air, cooking fumes, or talking) can trigger violent coughing.
In simple terms: The lungs are "dehydrated" (yin deficiency), and there's still a bit of "deficient fire" (residual heat) burning, causing a dry, itchy throat, sensitive airways, and a persistent cough. At this stage, simply using strong cough suppressants or antibiotics is often ineffective and may even trap the pathogen inside. The fundamental treatment lies in nourishing lung yin, clearing residual heat, and repairing the lung collaterals.
How Does TCM Regulate and Treat Persistent Post-COVID Throat Itch and Cough?
Dr. Que Poh Yuen Albert has extensive experience in treating lingering post-COVID cough. He skillfully uses the classic formula Yangyin Qingfei Decoction (Nourish Yin and Clear the Lungs Decoction) with modifications. This formula originates from the Qing Dynasty medical text "Chong Lou Yu Yao" (Jade Key to the Secluded Chamber) by physician Zheng Shouquan. It has the effects of nourishing yin, clearing the lungs, resolving toxins, and benefiting the throat.
Yangyin Qingfei Decoction is composed of: Sheng Dihuang (Raw Rehmannia Root), Maidong (Ophiopogon Root), Xuanshen (Scrophularia Root), Sheng Gancao (Raw Licorice Root), Bohe (Mint), Beimu (Fritillaria Bulb), Danpi (Moutan Bark), and Baishao (White Peony Root).
Sovereign Herb (Jun): Sheng Dihuang (Raw Rehmannia Root): Greatly supplements true yin, clears heat and cools blood, nourishes lung and kidney yin - "replenishes water" at the root.
Minister Herbs (Chen): Maidong (Ophiopogon Root) & Xuanshen (Scrophularia Root): Powerfully nourish yin and promote fluid production, moisten the lungs and benefit the throat, clear and descend deficient fire - specifically treat dry mouth, throat dryness, itch, and pain.
Baishao (White Peony Root): Nourishes blood and astringes yin, softens the liver and relaxes tension - helps relieve spasmodic cough caused by bronchial spasm.
Assistant Herbs (Zuo):
Danpi (Moutan Bark): Cools blood and clears heat, disperses stasis and reduces swelling - clears lingering stagnant heat in the lung collaterals.
Chuan Beimu (Sichuan Fritillaria Bulb): Moistens the lungs and transforms phlegm, dissipates nodules and stops cough - especially good for dry cough with little phlegm.
Guide Herb (Shi):
Bohe (Mint): Pungent and cool, diffuses and vents, benefits the throat and clears the voice - rapidly relieves throat itch and discomfort, providing a "vent" for the whole formula.
Sheng Gancao (Raw Licorice Root): Clears heat and resolves toxins, moistens the lungs and stops cough, harmonizes the other herbs.
The combined action of the formula:
Nourishes Yin and Moistens Dryness, Increases Fluids to "Extinguish Fire": Fundamentally replenishes lung yin fluids, extinguishes deficient fire, improving the "soil" of throat dryness and itch.
Clears Heat and Benefits the Throat, Relieves Irritation: Clears residual heat, acts directly on the throat to reduce itch and pain, lowering airway sensitivity.
Moistens the Lungs and Stops Cough, Repairs Lung Collaterals: Promotes recovery of lung function, reduces cough frequency and intensity.
Dr. Que Poh Yuen Albert emphasizes that clinical application requires precise modifications based on individual differences:
For severe cough, add Pipaye (Loquat Leaf) and Kuandonghua (Common Coltsfoot Flower) to enhance lung-moistening and cough-stopping power.
For sticky, difficult-to-expectorate phlegm (small amount), add Gualoupi (Snakegourd Peel) and Nanshashen (Adenophora Root).
If accompanied by qi deficiency and fatigue, consider adding Taizishen (Pseudostellaria Root) or Xiyangshen (American Ginseng) to boost qi and nourish yin.
If sleep is poor due to cough, add Suanzaoren (Spine Date Seed) and Hehuanpi (Silktree Albizia Bark) to calm the spirit and aid sleep.
Medical Case
Patient: Ms. Wang, 27 years old.
Chief Complaint: Developed high fever for 3 days after COVID infection, then tested negative. However, persistent cough for nearly 2 weeks, mainly characterized by intense throat itch, dry cough with no phlegm or scant sticky phlegm, especially severe at night and early morning, often waking from coughing. Accompanied by dry mouth and tongue, hoarse voice. Tried various cough syrups, lozenges, and even antibiotics with minimal effect. Feeling exhausted and anxious.
Initial Consultation: Red tongue body with scant moisture, thin slightly yellow and dry coating, thready and slightly rapid pulse.
Syndrome Differentiation: Epidemic toxin damaging yin, lung dryness and fluid depletion, residual heat unresolved.
Treatment Principle: Nourish yin and clear the lungs, moisten dryness and benefit the throat, assisted by calming the spirit.
Prescription: Modified Yangyin Qingfei Decoction:
Sheng Dihuang (Raw Rehmannia) 15g, Maidong (Ophiopogon) 12g, Xuanshen (Scrophularia) 12g, Baishao (White Peony) 10g,
Danpi (Moutan Bark) 8g, Chuan Beimu (Sichuan Fritillaria) (powder, taken infused) 6g,
Bohe (Mint) (added last) 5g, Sheng Gancao (Raw Licorice) 6g,
Added: Pipaye (Loquat Leaf) 10g, Beishashen (Glehnia Root) 12g, Suanzaoren (Spine Date Seed) 15g.
7 doses. 1 dose daily, decocted in water, taken warm twice a day.
Follow-up Consultation: Ms. Wang reported happily that after 3 days of medication, the throat itch significantly reduced, nighttime coughing decreased, and she could sleep more soundly. After finishing the 7 doses, the cough was 70-80% gone, dry mouth improved, and voice gradually became clear. Director Chen maintained the formula with slight adjustments (removed Suanzaoren, reduced Bohe dosage), prescribed another 5 doses for consolidation.
Result: Follow-up showed the cough did not recur. Sleep and spirit were both excellent.
