Patients with light infections are usually asymptomatic. "Ground itch" (papule or vesicle) may occur at the time of larva penetration of the skin. Epigastric pain, diarrhea, and eosinophilia occur about 30-45 days later. [PPID, p. 3203]
Hookworm disease, an intestinal nematode infection, is widespread in tropical and subtropical areas lacking adequate sanitary disposal of human wastes. The disease affects more than 10% of the world's population and is a significant cause of iron-deficient anemia and malnutrition. Larvae in soil are infective for several weeks. Larvae infect by penetrating the skin, usually the feet. Wearing shoes prevents infections by N. americanus, but not all infections by A. duodenale, which can infect by ingestion. Humans are the only reservoirs for both species of hookworm; therefore, effective sanitation will prevent infections.
The degree of anemia reflects the severity of infection. Patients with heavy infections may have diarrhea, epigastric ulcer-like pain, and stool positive for occult blood. During the lung-migration phase, larvae invade the lungs and may cause transient tracheitis with coughing, wheezing, fever, and blood-tinged sputum. Marked eosinophilia is associated with larval migration. Otherwise, eosinophilia is low or absent. A rash, "ground itch," may appear at the site of the penetrating larvae. Urticaria may be seen during the lung-migration phase. Other findings that sometimes occur: constipation, diarrhea, fatigue, dizziness, and pneumonia. Vomiting is a symptom after ingestion of A. duodenale. The sites of skin entry may appear as vesicles or pustules. Overwhelming infection can cause coma and death. [Cohen, p. 1133; ID, p. 1533, 2359-60; Guerrant, p. 799-804, 943, 961; CCDM, p. 295-7, 613; PPID, p. 3203-4; Cecil, p. 2066]
For updated text and symptoms of infectious diseases, see iddx.com.