What is Marasmus vs Kwashiorkor: Understanding Two Forms of Severe Malnutrition

November 18, 2025 •

4 min read

Worldwide, approximately 45% of deaths among children under five are linked to undernutrition. These deaths are often caused by severe conditions like marasmus and kwashiorkor, which represent two distinct variations of protein-energy malnutrition.

Quick Summary

Marasmus and kwashiorkor are distinct forms of severe malnutrition. Marasmus results from a total calorie and protein deficiency, causing severe wasting, while kwashiorkor is primarily a protein deficiency, leading to edema and a swollen appearance despite a potentially adequate calorie intake. The symptoms, causes, and treatment approaches differ significantly between the two conditions.

Key Points

Nutrient Deficiency: Marasmus results from a deficiency of both calories and protein, whereas kwashiorkor is primarily a severe protein deficiency, even with adequate calorie intake.
Clinical Appearance: The defining difference is the presence of edema (swelling) in kwashiorkor, which is absent in marasmus. Marasmus causes severe emaciation and a 'skin and bones' appearance.
Metabolic Response: In marasmus, the body breaks down its own fat and muscle for energy, while in kwashiorkor, the lack of protein synthesis leads to fluid leakage and edema.
Age of Onset: Marasmus often affects younger infants, typically under one year of age, while kwashiorkor is more common in slightly older children (1-3 years) after weaning.
Risk of Refeeding Syndrome: Both conditions require cautious nutritional rehabilitation to prevent refeeding syndrome, a dangerous metabolic complication that can occur if feeding is too rapid.
Treatment Approach: The treatment for both begins with stabilizing electrolytes and rehydrating the patient before slowly reintroducing nutrients, followed by a period of catch-up growth.

What is Protein-Energy Malnutrition?

Protein-energy malnutrition (PEM) is a severe state of undernutrition caused by a deficiency of protein, energy-rich foods (carbohydrates and fats), or both. While both marasmus and kwashiorkor fall under the umbrella of severe acute malnutrition (SAM), their specific deficiencies, clinical manifestations, and underlying metabolic processes are different. Understanding the defining characteristics of each is crucial for proper diagnosis and effective treatment, particularly in children who are most vulnerable.

The Body's Response to Starvation

In cases of inadequate nutrient intake, the body's physiological response differs depending on the nature of the deficiency. In marasmus, where there is a generalized lack of calories, the body adapts by breaking down its own tissues for energy. It first consumes its stored fat and then proceeds to muscle tissue. This leads to the characteristic severe emaciation seen in marasmic individuals. The body also lowers its metabolic rate to conserve energy, resulting in low heart rate, blood pressure, and body temperature.

Kwashiorkor, on the other hand, develops in a state of severe protein deficiency, often while the child still receives enough carbohydrates to meet their basic energy needs. The body’s inability to synthesize crucial proteins, particularly albumin, leads to a decrease in plasma osmotic pressure. This causes fluid to leak from the blood vessels into the interstitial tissues, resulting in the characteristic swelling, or edema, seen in kwashiorkor. The presence of edema can mask the underlying muscle wasting, making the individual appear less undernourished than they truly are.

Causes of Marasmus and Kwashiorkor

Both conditions are rooted in nutritional inadequacy but are triggered by different dietary patterns and circumstances.

Marasmus: The primary cause is a prolonged, severe deprivation of all macronutrients: protein, carbohydrates, and fats. This is commonly a result of poverty, famine, and food scarcity. It is often seen in infants under one year of age who are prematurely weaned from breast milk to diluted, low-calorie substitutes. Chronic or recurrent infections can also contribute by increasing nutrient requirements and interfering with absorption.
Kwashiorkor: This condition typically occurs in slightly older children (6 months to 3 years) who have been weaned off breast milk onto a diet high in carbohydrates but severely lacking in protein. In many low-resource areas, starchy foods like maize or cassava are staples but do not provide sufficient protein to support proper development. Infectious diseases can also precipitate kwashiorkor.

Comparison Table: Marasmus vs. Kwashiorkor


Feature	Marasmus	Kwashiorkor
Primary Deficiency	Total energy and protein	Primarily protein
Appearance	Emaciated, shriveled, 'skin and bones'	Edematous (swollen), moon face, distended belly
Edema (Swelling)	Absent	Present (pitting edema)
Subcutaneous Fat	Markedly reduced or absent	Preserved
Muscle Wasting	Severe and visible	Less visible due to edema, but present
Age of Onset	Typically under 1 year	Often between 1 and 3 years
Appetite	Poor appetite	Poor appetite, but sometimes described as voracious
Hair Changes	Dry and thin, less severe discoloration	Sparse, brittle, easily plucked; may have reddish or 'flag sign' discoloration
Skin Changes	Dry, thin, and wrinkled	Dermatosis with peeling, flaky 'paint' lesions
Fatty Liver	Absent	Present (hepatomegaly)
Behavioral Changes	Apathetic, but can be alert	Apathetic, irritable, lethargic

Clinical Manifestations and Treatment Approaches

The difference in underlying nutritional deficiencies means that the body's system-wide response also varies.

Clinical Manifestations

Marasmus: The most obvious sign is extreme wasting. Children with marasmus appear gaunt, with their ribs and bones visible and their skin loose and wrinkled, giving an 'old man' look. Growth is severely stunted. The body attempts to maintain its core functions, but the immune system is significantly weakened, increasing the risk of infections.
Kwashiorkor: While muscle wasting occurs, it is masked by the edema, which is the hallmark of the disease. Swelling is most notable in the feet, legs, face, and abdomen. The liver can become enlarged and fatty. Children with kwashiorkor often have a distinct apathy and irritability. Changes in hair and skin pigmentation are also common.

Treatment Protocols

Both conditions require immediate and carefully managed medical intervention to prevent further complications like refeeding syndrome.

Rehydration and Stabilization: The first step involves treating shock, correcting electrolyte imbalances, and rehydrating the patient slowly, using specialized solutions like ReSoMal. This is a critical stage to avoid overloading the compromised system.
Cautious Feeding: After stabilization, nutritional rehabilitation begins. Feeding formulas like F-75, low in protein but high in energy, are used to provide gradual, continuous nutrition. The focus is on rebuilding the body's functions safely without shocking the system with too many nutrients at once.
Catch-Up Growth and Rehabilitation: Once stable, the child's caloric and protein intake is increased to promote rapid catch-up growth using higher-energy formulas like F-100. Treatment also includes addressing any underlying infections with antibiotics and providing emotional and developmental support.

Prevention is Key

Prevention efforts focus on improving nutrition and sanitation, especially in resource-limited settings. This includes promoting exclusive breastfeeding for the first six months of life, ensuring access to balanced complementary foods after weaning, providing nutritional education, and treating underlying infections. Addressing socio-economic factors like poverty and food insecurity is essential for long-term prevention.

Conclusion

While both marasmus and kwashiorkor are serious forms of severe acute malnutrition, they present with different primary deficiencies and clinical signs. Marasmus is characterized by an overall energy and protein deficit, leading to severe wasting, while kwashiorkor results from a severe protein deficiency, manifesting as edema. Both conditions are life-threatening but can be treated successfully with proper medical care, focused on stabilization, gradual re-nutrition, and managing any infections. Understanding these crucial distinctions is vital for effective diagnosis and management in vulnerable populations.

Learn more about the pathophysiology of severe acute malnutrition here.

Frequently Asked Questions

The main difference is the primary nutritional cause and the resulting physical appearance. Marasmus is a deficiency of both calories and protein, leading to severe wasting and emaciation. Kwashiorkor is primarily a protein deficiency, which results in edema (swelling) that can mask muscle wasting.

A child with marasmus appears severely underweight and emaciated, with significant loss of muscle mass and subcutaneous fat. They often have loose, wrinkled skin and may have a 'monkey-like' or 'old man' facial appearance.

A child with kwashiorkor often has a swollen appearance due to edema, particularly in the abdomen, face, and extremities. The swelling can hide underlying muscle wasting. They may also have skin lesions, hair discoloration, and a rounded face.

Both are life-threatening forms of malnutrition. However, kwashiorkor can have a higher acute mortality risk due to rapid fluid shifts and metabolic imbalances, especially during treatment, which makes it particularly dangerous.

Marasmus is often seen in infants under one year, while kwashiorkor typically affects children between one and three years of age, often around the time of weaning.

Yes, it is possible for a person to have a combination of both conditions, which is known as marasmic kwashiorkor. This presents with both gross wasting and edema.

Treatment is administered in stages under medical supervision and involves: 1) initial stabilization and rehydration with special solutions like ReSoMal, 2) slow, cautious refeeding with carefully balanced formulas, and 3) full nutritional rehabilitation to promote catch-up growth. Any underlying infections are also treated.