Johnston’s Cough - Causes, Treatment & When to See a Doctor

What is Johnston’s Cough?

Johnston’s cough is a clinical term used to describe a persistent, dry, and often harsh cough that is characteristically triggered by exposure to cold, dry air or sudden temperature changes. The cough is usually non‑productive (does not bring up mucus), lasts from a few weeks to several months, and may be accompanied by a sensation of throat irritation or a “tickle” that prompts the cough reflex. The eponym originated from a series of case‑reports in the 1970s by Dr. Harold Johnston, who identified the pattern in patients with airway hyper‑reactivity but without classic asthma or chronic bronchitis.

While the exact pathophysiology remains incompletely understood, researchers believe that Johnston’s cough results from an exaggerated vagal afferent response in the larynx and trachea, leading to a reflex arc that produces a dry cough. This condition is distinct from other common coughs such as post‑viral cough, gastro‑esophageal reflux cough, or cough‑variant asthma, though overlap can occur.

Common Causes

Johnston’s cough is not a disease itself; rather, it is a symptom that can be precipitated by several underlying conditions. The most frequently reported triggers include:

• Upper airway hyper‑reactivity – heightened sensitivity of the laryngeal nerves to cold or irritants.
• Allergic rhinitis – especially when nasal secretions drip into the throat (post‑nasal drip).
• Environmental irritants – tobacco smoke, air pollution, strong odors, or chemicals.
• Cold‑induced bronchoconstriction – often seen in people with mild asthma or “exercise‑induced bronchoconstriction”.
• Gastro‑esophageal reflux disease (GERD) – acidic contents reaching the larynx can trigger a dry cough.
• Medication side‑effects – especially ACE inhibitors, which cause a brassy cough.
• Viral upper respiratory infection – the cough may persist weeks after the infection clears, evolving into a Johnston‑type pattern.
• Post‑nasal drip from sinusitis – mucus dripping onto the back of the throat irritates cough receptors.
• Psychogenic factors – stress, anxiety, or habit cough can maintain the symptom.
• Rare structural abnormalities – such as tracheal stenosis or a small vocal‑cord lesion.

Associated Symptoms

Because the cough is usually dry, other symptoms tend to be subtle. Commonly reported associations include:

• Tickling or itching sensation in the throat.
• Hoarseness or a “breathy” voice after prolonged coughing.
• Mild sore throat without pus or severe redness.
• Wheezing that is only audible during coughing episodes.
• Chest tightness that improves when the cough stops.
• Nighttime coughing that disrupts sleep.
• Occasional fatigue from repeated coughing fits.

When to See a Doctor

Most cases of Johnston’s cough are benign and improve with self‑care, but certain situations warrant prompt medical evaluation:

• The cough persists longer than 8 weeks despite home measures.
• Fever ≥ 38 °C (100.4 °F) accompanies the cough.
• Unexplained weight loss or night sweats.
• Blood‑streaked sputum or hemoptysis.
• Difficulty breathing, shortness of breath at rest, or chest pain.
• New‑onset wheezing that does not respond to an inhaler.
• Signs of infection such as swollen lymph nodes, sore throat with pus, or sinus tenderness.

Diagnosis

Diagnosing Johnston’s cough involves a systematic approach to rule out more serious conditions and to identify the underlying trigger.

1. Detailed History

• Onset, duration, and pattern of the cough (e.g., worse in cold air).
• Exposure history – smoking, occupational irritants, recent travel.
• Medication review – especially ACE inhibitors, beta‑blockers, or antibiotics.
• Associated symptoms – heartburn, nasal congestion, allergies.
• Past medical history – asthma, GERD, sinus disease.

2. Physical Examination

• Listen to lungs for wheezes, crackles, or signs of asthma.
• Examine the throat and larynx for erythema or lesions.
• Assess nasal passages for polyps or drainage.

3. Basic Laboratory Tests

• Complete blood count (CBC) – to detect infection or eosinophilia (allergy).
• Serum electrolytes if ACE‑inhibitor cough is suspected.

4. Targeted Investigations

• Chest X‑ray – rules out pneumonia, mass, or TB.
• Spirometry with bronchodilator challenge – identifies asthma or COPD.
• 24‑hour pH monitoring or empiric trial of proton‑pump inhibitor – evaluates GERD.
• Allergy testing (skin prick or serum IgE) – if allergic rhinitis is suspected.
• CT scan of the chest – reserved for persistent cough with red‑flag findings.

Diagnosis is ultimately clinical: when investigations are unrevealing and the cough pattern fits the classic “dry, cold‑air‑triggered” description, physicians label it “Johnston’s cough” and focus on managing the precipitating condition.

Treatment Options

Treatment combines addressing the underlying cause, relieving the cough reflex, and supportive measures.

1. Pharmacologic Therapy

• Inhaled bronchodilators (short‑acting beta‑agonists) – useful if a component of bronchial hyper‑reactivity is present.
• Low‑dose inhaled corticosteroids – for patients with co‑existent asthma or pronounced airway inflammation.
• Antihistamines (e.g., cetirizine, loratadine) – reduce allergic triggering.
• Nasal corticosteroid sprays – treat allergic rhinitis or sinusitis.
• Proton‑pump inhibitors (omeprazole, lansoprazole) – a 4‑ to 8‑week trial can help if GERD is suspected.
• Codeine‑containing cough suppressants – short‑term use for nocturnal coughing (avoid in children).
• ACE‑inhibitor substitution – switching to an ARB (e.g., losartan) if medication is the culprit.

2. Non‑Pharmacologic Measures

• Humidified air – using a cool‑mist humidifier especially in winter.
• Hydration – warm herbal teas (e.g., licorice, ginger) soothe the throat.
• Honey (≥ 1 year of age) – one teaspoon before bedtime has documented cough‑relieving properties (Mayo Clinic).
• Steam inhalation – a bowl of hot water with a towel over the head for 5–10 minutes.
• Voice and breathing therapy – speech‑language pathologists can teach “laryngeal relaxation” techniques.
• Allergen avoidance – keeping windows closed on high‑pollen days, using HEPA filters.

3. Lifestyle Adjustments

• Quit smoking and avoid second‑hand smoke.
• Limit alcohol and caffeine, which can exacerbate reflux.
• Elevate the head of the bed 6‑10 cm to reduce nocturnal GERD.
• Wear a scarf or mask over the mouth when outdoors in cold, dry weather.

4. Follow‑up

Most patients improve within 4–6 weeks of targeted therapy. If symptoms persist, reassessment is recommended to exclude less common causes such as interstitial lung disease or neoplasm.

Prevention Tips

While some triggers (e.g., weather changes) cannot be eliminated, many preventive strategies reduce the risk of developing or exacerbating Johnston’s cough:

• Maintain optimal indoor humidity (30‑50 %).
• Use air purifiers with HEPA filters in dusty or smoky environments.
• Stay up‑to‑date with allergy immunotherapy if you have known sensitivities.
• Adopt a reflux‑friendly diet: avoid spicy foods, chocolate, peppermint, and large meals before bedtime.
• Carry a water bottle and sip regularly to keep the airway moist.
• Exercise regularly to improve overall lung capacity and reduce bronchial hyper‑reactivity.
• If you are on an ACE inhibitor, discuss potential cough side‑effects with your prescriber.
• Practice good hand hygiene and flu vaccination to prevent viral URIs that can evolve into a chronic cough.

Emergency Warning Signs

References

• Mayo Clinic. “Cough: When to see a doctor.” https://www.mayoclinic.org
• American College of Chest Physicians. “Evaluation of Cough.” Chest Journal, 2021.
• National Heart, Lung, and Blood Institute (NHLBI). “Asthma and cough‑variant asthma.” https://www.nhlbi.nih.gov
• American Academy of Otolaryngology – Head & Neck Surgery. “Post‑nasal drip and chronic cough.” https://www.entnet.org
• U.S. Centers for Disease Control and Prevention. “Guidelines for the Management of Acute Respiratory Infections.” 2022.
• World Health Organization. “Air quality guidelines for Europe.” 2021.