Most people with salmonellosis develop diarrhea, fever, vomiting, and abdominal cramps 12 to 72 hours after infection.[3] Diarrhea is often mucopurulent (containing mucus or pus) and bloody. In most cases, the illness lasts four to seven days, and most people recover without treatment. In some cases, though, the diarrhea may be so severe that the patient becomes dangerously dehydrated and must be taken to a hospital. At the hospital, the patient may receive intravenous fluids to treat the dehydration, and may be given medications to provide symptomatic relief, such as fever reduction. In severe cases, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites, and can cause death, unless the person is treated promptly with antibiotics.
In otherwise healthy adults, the symptoms can be mild. Normally, no sepsis occurs, but it can occur exceptionally as a complication in the immunocompromised. However, in people at risk such as infants, small children, the elderly, Salmonella infections can become very serious, leading to complications. In infants, dehydration can cause a state of severe toxicity. Extraintestinal localizations are possible, especially Salmonella meningitis in children, osteitis, etc. Children with sickle cell anaemia who are infected with Salmonella may develop osteomyelitis. Treatment of osteomyelitis, in this case, will be to use fluoroquinolones (Ciproflaxacin, Levofloxacin, etc. and Nalidixic acid).
Those whose only symptom is diarrhea usually completely recover, but it can be several months until their bowel habits are normal.[4] A small number of people afflicted with salmonellosis experience reactive arthritis, which can last months or years and can lead to chronic arthritis.[5][6] In sickle-cell anemia, osteomyelitis due to Salmonella infection is much more common than in the general population. Though Salmonella infection is frequently the cause of osteomyelitis in sickle-cell anemia patients, it is not the most common cause; the most common cause remains Staphylococcus infection.