An 18-month-old child has wrinkled facies and loss of subcutaneous fat. What is the likely diagnosis?

The presentation of wrinkled facies and loss of subcutaneous fat in an 18-month-old child suggests a diagnosis of marasmus. Marasmus is a form of severe malnutrition typically resulting from inadequate caloric intake and is more common in children with limited access to food or in situations of neglect or chronic illness.

In children with marasmus, physical examination may reveal features such as significant weight loss, emaciation, and a decrease in subcutaneous fat, which contributes to the characteristic wrinkled appearance of the skin. This condition primarily affects children aged 6 months to 2 years and is associated with a severe deficiency of calories and protein, leading to a more pronounced presentation of malnutrition.

Kwashiorkor, although also a form of malnutrition, typically presents with a more swollen appearance due to edema, as a result of protein deficiency along with sufficient or excessive caloric intake. Pellagra is related to niacin deficiency, which presents with dermatitis, diarrhea, and dementia, and does not usually cause wrinkled facies or loss of subcutaneous fat specifically. Rickets, a vitamin D deficiency, leads to bone deformities rather than the skin and fat changes observed in marasmus. Thus, the clinical findings align most