The symptoms of hookworm range from subtle or unnoticeable to severe and life-altering. The intensity of symptoms depends on factors such as worm burden, nutritional status, and previous exposure. While many individuals remain asymptomatic, others—particularly children, pregnant women, and those who are malnourished—may experience serious health consequences. Recognizing these symptoms early is essential for timely treatment and prevention of complications.
Early Symptoms: Skin Reactions
The first sign of hookworm infection often appears at the site of larval penetration, commonly on the feet or lower legs. This reaction, known as “ground itch,” manifests as:
- Redness and swelling
- Intense itching
- A localized rash
Ground itch usually resolves within days, but repeated exposure can cause more severe inflammation and even secondary bacterial infections from scratching.
Pulmonary Phase: Respiratory Symptoms
After penetrating the skin, larvae travel through the bloodstream to the lungs, where they may trigger mild respiratory issues, such as:
- Dry cough
- Sore throat
- Wheezing
These symptoms are frequently misdiagnosed as a viral infection because the pulmonary phase is short-lived. Severe cases or individuals with pre-existing lung problems may experience bronchospasm or mild haemoptysis (coughing up blood).
Intestinal Phase: Gastrointestinal and Systemic Effects
Once the larvae reach the small intestine and mature into adult worms, systemic symptoms become more apparent. The hallmark of hookworm infection is iron-deficiency anaemia, caused by chronic blood loss at the worm attachment sites. Each adult hookworm consumes 0.2–0.3 mL of blood per day, leading to gradual but significant blood depletion in heavy infections.
Common symptoms include:
- Fatigue and persistent weakness
- Pallor (pale skin)
- Shortness of breath during activity
- Dizziness or lightheadedness
- Cold intolerance and brittle nails
Impact on Children
In children, chronic anaemia can cause:
- Growth stunting
- Developmental delays
- Cognitive impairment
- Poor school performance
These effects may persist even after treatment if nutritional deficiencies were severe or prolonged.
Abdominal Discomfort and Digestive Symptoms
Gastrointestinal manifestations include:
- Vague abdominal pain
- Bloating or nausea
- Loss of appetite
- Occasional diarrhoea or constipation
In heavy infections, intestinal inflammation reduces nutrient absorption, contributing to protein-energy malnutrition.
Effects on Pregnant Women
In pregnancy, hookworm infection is particularly dangerous because of increased nutritional demands. Associated risks include:
- Maternal anaemia
- Preterm birth
- Low birth weight
- Increased maternal morbidity
The World Health Organization recommends deworming during the second and third trimesters in endemic regions to reduce these risks.
Severe and Rare Manifestations
In very heavy infections, chronic anaemia may lead to cardiovascular strain, including:
- Rapid heartbeat (tachycardia)
- Palpitations
- In rare cases, cardiac failure
Another rare outcome, particularly with oral ingestion of larvae (Ancylostoma duodenale), is eosinophilic gastroenteritis, which causes abdominal pain and allergic-type inflammation of the gut.
Chronic and Social Impact
Repeated or chronic infection leads to persistent fatigue, low work productivity, and greater vulnerability to other illnesses. This has a direct effect on quality of life, economic stability, and education outcomes, especially in resource-limited communities.
Summary of Symptoms
To summarise, hookworm symptoms progress in stages:
- Early skin irritation (ground itch)
- Mild respiratory symptoms during larval migration
- Chronic anaemia and malnutrition in the intestinal phase
The severity depends on worm load, nutritional status, and access to healthcare. Because symptoms are often subtle and develop gradually, regular screening and preventive programs remain critical in endemic regions.
