COVID-19 Signs and Symptoms
COVID-19 most commonly presents with fever (92.8% of patients), dry cough (69.8%), and loss of taste and smell (anosmia 85.6%, ageusia 88.8%), with the latter being stronger predictors of COVID-19 than fever itself. 1
Primary Respiratory Symptoms
- Fever remains the most typical symptom, present in 92.8% of patients, and should be considered the hallmark presentation 2, 1
- Dry cough occurs in 69.8% of cases and is characteristically non-productive 2, 1
- Dyspnea (shortness of breath) is strongly associated with severe disease (odds ratio 2.43) and warrants immediate medical attention 2, 1
- Upper respiratory symptoms including nasal congestion and runny nose occur in only 4.0% of patients, making them less common than in typical viral infections 2, 1
- Sore throat is present in only 5.1% of patients 1
Highly Specific Symptoms (Key Differentiators)
- Loss of smell (anosmia) occurs in 85.6% of patients and is significantly more common in COVID-19 than influenza 2, 1
- Loss of taste (ageusia) occurs in 88.8% of patients and serves as a stronger predictor of COVID-19 than self-reported fever 2, 1
- These sensory losses can occur suddenly and may present as the only symptoms 1
Constitutional Symptoms
- Fatigue is present in 38.5% of patients and can be profound 2, 1
- Myalgia (muscle pain) occurs in 27.7% of cases 1
- Headache is reported in 7.2% of patients 1
Gastrointestinal Manifestations
- Diarrhea and other GI symptoms occur in 6.1% of patients 2, 1
- Patients presenting with GI symptoms (anorexia, nausea, vomiting, diarrhea) may have higher risk of negative outcomes 3
- Abdominal pain can occur as part of the symptom complex 4
Severe Disease Indicators (Red Flags)
Severe COVID-19 (14% of cases) is characterized by:
- Respiratory rate ≥30 breaths/min 1
- Blood oxygen saturation ≤93% 1
- PaO2/FiO2 ratio <300 1
- Lung infiltrates >50% within 24-48 hours 1
Critical disease (5% of cases) manifests as:
- Respiratory failure requiring mechanical ventilation 1
- Septic shock 2
- Multiple organ dysfunction or failure 2, 1
Physical Examination Findings
- Mild cases may show no positive physical signs 2
- Severe cases demonstrate shortness of breath, moist rales in lungs, weakened breath sounds, dullness on percussion, and altered tactile speech tremor 2
Extrapulmonary Complications
Beyond respiratory symptoms, COVID-19 can cause:
- Cardiovascular: Myocarditis, arrhythmias, cardiomyopathy, thromboembolism 2
- Neurological: Encephalopathy, peripheral neuropathy, cerebral venous thrombosis 2
- Hematologic: Thrombophilia, microvascular thrombosis 2
- Dermatologic: Skin changes, livedo reticularis 2
- Ocular: Various eye symptoms 2
- Metabolic: New-onset or acute worsening of hyperglycemia 2
- Musculoskeletal: Rhabdomyolysis 2
Special Populations
Children:
- Often asymptomatic or present with only a few symptoms (up to 45% asymptomatic in surveillance testing) 2
- Most common symptoms in hospitalized children: fever, nausea/vomiting, cough, shortness of breath, and upper respiratory symptoms 2
- May present with fever, fatigue, cough, nasal congestion, runny nose, expectoration, diarrhea, and headache 1
- Risk of multisystem inflammatory syndrome in children (MIS-C) 2
Pregnant women:
- At increased risk for severe illness 2
- COVID-19 may be associated with pregnancy loss and adverse pregnancy outcomes 2
Disease Severity Distribution
- Mild cases (81%): Non-pneumonia or mild pneumonia 1
- Severe cases (14%): Meeting criteria listed above 1
- Critical cases (5%): Respiratory failure, shock, or multi-organ failure 1
Common Pitfalls
Avoid assuming COVID-19 is absent based on:
- Absence of fever alone, as other symptoms may predominate 1
- Presence of upper respiratory symptoms like runny nose, which are actually uncommon in COVID-19 1
- Normal initial presentation in children, who frequently have minimal or no symptoms 2
Key differentiator from influenza: Loss of taste and smell are significantly more common in COVID-19 and should raise strong suspicion even when other symptoms are mild 1