Kwashiorkor occurs most commonly in areas of famine, limited food supply, and low levels of education, which can lead to inadequate knowledge of proper diet.

Early symptoms of any type of malnutrition are very general and include fatigue, irritability, and lethargy. As protein deprivation continues, growth failure, loss of muscle mass, generalized swelling (edema), and decreased immunity occur.

A large, protuberant belly is common. Skin conditions (such as dermatitis, changes in pigmentation, thinning of hair, and vitiligo) are seen frequently. Shock and coma precede death.

The incidence of kwashiorkor in children in the U.S. is extremely low and only rare, isolated cases are seen.

This is typically a disease of impoverished countries, and is often seen in the midst of drought or political turmoil. However, one government estimate suggests that as many as 50% of elderly persons in nursing homes in the U.S. suffer from protein-calorie malnutrition.

Improving calorie and protein intake will correct kwashiorkor, provided that treatment is not started too late. However, full height and growth potential will never be achieved in children who have had this condition.

Severe kwashiorkor may leave a child with permanent mental and physical disabilities. There is good statistical evidence that malnutrition early in life permanently decreases IQ.

Risk factors include living in impoverished countries, countries in political unrest, and countries affected by frequent natural disasters (such as drought). These conditions are directly or indirectly responsible for scarcity of food which leads to malnutrition.