What is marasmus and kwashiorkor malnutrition?

October 26, 2025 •

2 min read

Severe acute malnutrition, encompassing both marasmus and kwashiorkor malnutrition, is a significant global health concern and is linked to nearly half of all preventable deaths in children under five. These are two distinct but related forms of protein-energy malnutrition (PEM), each with unique signs, underlying causes, and clinical approaches to treatment.

Quick Summary

Marasmus results from an overall calorie deficiency leading to severe wasting, while kwashiorkor is characterized by a primary protein deficiency that causes edema. Both are severe forms of protein-energy malnutrition with different physiological impacts.

Key Points

Marasmus is overall starvation: It is a severe deficiency of total calories, including protein, carbohydrates, and fats, leading to extreme wasting and an emaciated appearance.
Kwashiorkor is specific protein deficiency: It develops when protein intake is severely lacking despite relatively sufficient calorie consumption, leading to distinct symptoms like edema and a distended belly.
Edema is a key differentiator: The swelling (edema) caused by kwashiorkor masks the severity of malnutrition and is completely absent in marasmus.
Visible signs are different: Marasmus presents with a 'skin and bones' appearance and loose skin folds, while kwashiorkor is characterized by a bloated belly, round face, and skin/hair color changes.
Treatment requires caution: The recovery process for both conditions must be gradual and carefully managed to avoid life-threatening refeeding syndrome, with specific protocols developed by the WHO.
Both are preventable: Strategies focusing on nutritional education, breastfeeding promotion, improved sanitation, and poverty reduction are essential for prevention.

What is Marasmus?

Marasmus is a severe form of protein-energy undernutrition (PEU) caused by an overall deficiency of all macronutrients—carbohydrates, fats, and proteins. It is most common in infants and very young children but can affect any age group suffering from prolonged starvation. Symptoms and characteristics of marasmus include extreme emaciation, visible wasting, a wrinkled facial appearance, loose skin, apathy, lethargy, and stunted growth.

What is Kwashiorkor?

Kwashiorkor is another form of PEU, primarily resulting from a severe deficiency of dietary protein, even when calorie intake is somewhat adequate. It often affects older infants and young children who are weaned onto starchy, low-protein diets. Symptoms and characteristics of kwashiorkor include characteristic edema, a distended abdomen, and changes in skin and hair. Children are often listless and irritable. Muscle mass is reduced, although often masked by edema.

Comparison of Marasmus and Kwashiorkor

Despite being forms of severe malnutrition, marasmus and kwashiorkor have key differences:


Feature	Marasmus	Kwashiorkor
Primary Deficiency	Overall calories and all macronutrients	Primarily protein, with relatively adequate caloric intake
Edema (Swelling)	Absent	Present, especially in extremities and face
Body Appearance	Severely emaciated, 'skin and bones'	Puffy or swollen, with a distended abdomen
Muscle and Fat Wasting	Marked wasting of both muscle and fat	Muscle wasting present, but some subcutaneous fat is retained
Skin and Hair	Dry, loose, and wrinkled skin; hair may be thin	Skin lesions, discoloration, and sparse, brittle, discolored hair
Appetite	Typically good, often described as ravenous	Poor or diminished

Causes, Diagnosis, and Treatment

Root Causes

Poverty and food insecurity are primary drivers, especially in developing nations. Other causes include inadequate nutrition during growth, infectious diseases like diarrhea, inappropriate feeding practices, and underlying medical conditions.

Diagnosis

Diagnosis involves clinical assessment and tests. Methods include: Physical Examination, Anthropometric Measurements, and Laboratory Tests.

Treatment

Treatment is a medical emergency requiring a phased approach to prevent complications like refeeding syndrome. The WHO outlines a plan for severe acute malnutrition, including Stabilization, Rehabilitation, and Follow-up and Prevention.

Prevention Strategies

Preventing marasmus and kwashiorkor involves addressing root causes and implementing proactive strategies, such as promoting proper feeding practices, enhancing nutritional education, improving socioeconomic conditions, and strengthening public health systems.

Conclusion

Marasmus and kwashiorkor are severe forms of malnutrition with distinct presentations, caused by a lack of calories, protein, or both. Marasmus is characterized by extreme wasting, while kwashiorkor involves edema. Both require careful medical treatment and are preventable through public health and nutritional interventions {Link: World Health Organization https://www.who.int/health-topics/malnutrition}.

Frequently Asked Questions

The main difference lies in the nutritional deficiency. Marasmus is caused by an overall deficiency of calories and protein, leading to severe emaciation. Kwashiorkor results primarily from a protein deficiency, even with some calorie intake, and causes characteristic edema or swelling.

Marasmus is caused by an insufficient intake of calories and nutrients, often resulting from food scarcity due to poverty, famine, or infectious diseases. In infants, it can be caused by inadequate breastfeeding or improper weaning.

Yes, kwashiorkor can occur even when an individual consumes enough calories if their diet is severely lacking in protein. This is common in children who are weaned from protein-rich breast milk and given a carbohydrate-heavy, low-protein diet.

Refeeding syndrome is a dangerous and potentially fatal complication that can occur when severely malnourished individuals are fed too quickly. It causes extreme and rapid shifts in fluid and electrolytes, which can lead to heart failure and other organ dysfunction.

While the prevalence is highest in resource-limited settings, malnutrition can affect individuals in any country. In developed nations, it can be a concern for the elderly, those with chronic diseases, or individuals with eating disorders like anorexia nervosa.

If left untreated or if treatment is delayed, both conditions can lead to severe and sometimes irreversible consequences. These can include stunted growth, intellectual and developmental delays, a compromised immune system, and an increased risk of chronic diseases.

Diagnosis involves a combination of clinical assessment, anthropometric measurements like weight-for-height and MUAC, and laboratory tests to measure serum protein levels and assess overall nutritional and metabolic status.