White Sputum: Differential Diagnosis from Cold to Heart Failure

White/clear sputum (mucoid) indicates non-purulent airway secretion. Differential spans benign to life-threatening.

Common Causes

Condition	Key Features
Viral URI / Cold	Clear/white, self-limited, + rhinorrhea, sore throat
Allergic rhinitis / post-nasal drip	Thin, clear; sneezing, itchy eyes
Asthma	White, sticky; + wheeze, dyspnea, diurnal variation
Chronic bronchitis (COPD)	Daily white/yellow sputum; + cough ≥3 mo/yr
GERD	White frothy; + heartburn, worse supine
Heart failure	Pink-frothy (acute) or white; + orthopnea, PND, edema
Bronchiectasis	Chronic copious; + recurrent infections
TB	Persistent >2 wks; + night sweats, weight loss; may be blood-tinged
COVID-19	Dry or white; + fever, anosmia, fatigue

Red Flags

• Hemoptysis (blood)
• Fever >38.5°C persistent
• Weight loss, night sweats
• Dyspnea at rest
• Immunocompromised

Diagnostic Approach

• History, exam, pulse oximetry.
• CXR, spirometry, sputum culture/PCR.
• BNP/NT-proBNP if HF suspected.
• CT chest if unclear.

Color alone isn't diagnostic; context and associated symptoms guide workup.