Malnutrition including anorexia nervosa
Malnutrition occurs when the supply of nutrients and energy is inadequate to meet the body's requirements.
Worldwide, the most common cause of malnutrition is inadequate food supply. Gastrointestinal infections, particularly parasitic infections, exacerbate this problem. Preschool-aged children in developing countries are most at risk because of their increased protein and energy requirements, greater susceptibility to infection, and exposure to unhygienic conditions. Marasmus and kwashiorkor are two related disorders of severe protein-energy malnutrition that occur mainly in young children from developing countries at the time of weaning.
In developed countries, other causes of malnutrition are more prominent:
- Reduced absorption or abnormal metabolism of nutrients and energy due to illnesses such as inflammatory bowel disease (e.g. Crohn disease), gastrointestinal infections, cystic fibrosis, extensive thermal burns, or cancer.
- Insufficient food intake e.g. anorexia nervosa.
- Complex social and medical problems – for example elderly people can become malnourished due to a combination of reduced appetite, impaired mental functioning, medications, coexisting illnesses, psychosocial isolation, heavy alcohol intake, and/or depression.
- Inadequate food supply can also be a problem in low-income areas of developed countries.
Dermatological features of malnutrition
Although malnutrition affects almost every organ in the body, this page focuses on the dermatological features.
|Xerosis (dry skin)||Due to deficiencies of vitamins and trace elements and possibly disordered thyroid function.|
|Telogen effluvium||Increased shedding of hair on the scalp which can occur following any significant physical or psychological stress. It may also follow a variety of vitamin deficiencies.|
|Nail abnormalities||Nails can become thin and soft and may have fissures (cracks) or ridges. Koilonychia (spoon-shaped nails) may develop due to iron deficiency.|
|Pale skin||Due to iron deficiency.|
|Glossitis (inflammation of the tongue)||Due to severe vitamin B and/or iron deficiency. The small bumps on the surface of the tongue (papillae) may become flattened, causing the tongue to appear smooth.|
|Angular stomatitis||Fissures at the corners of the mouth due to riboflavin and other vitamin deficiencies.|
|Pruritus (itch)||May be caused by xerosis, iron deficiency, or other consequences of malnutrition.|
|Non-healing wounds and bedsores||Due to vitamin C and zinc deficiency.|
|Acrocyanosis||Purple, cold hands and feet associated with circulatory system abnormalities. In rare cases, chilblains can develop.|
|Acrodermatitis enteropathica||Due to zinc deficiency.|
|Scurvy||Due to vitamin C deficiency.|
|Pellagra||Due to niacin deficiency.|
|Purpura||Due to starvation-related bone marrow depression and subsequent reduction in circulating platelets. Also seen in vitamin C deficiency.|
|Gingivitis||May result from severe vitamin D deficiency.|
When malnutrition is caused by anorexia nervosa, a number of specific dermatological features are seen:
|Lanugo hair||Fine, downy, pale hair on the back, abdomen, and forearms. Resolves when normal total body fat is restored.|
|Carotenaemia||Yellowing of the skin due to excessive intake of carrots, other yellow and green vegetables, and citrus fruit. Most evident on the soles and palms.|
|Self-inflicted wounds||Self-inflicted cutting or burning as well as trichotillomania (hair loss due to hair pulling) may be evident.|
|Pompholyx (blistering hand dermatitis)||A rare complication of anorexia nervosa.|
|Pili torti (twisted hair)||Possibly due to malnutrition combined with excessive ingestion of carotene containing fruit and vegetables.|
Skin changes associated with anorexia nervosa become more frequent when the body mass index (BMI) falls to 16 kg/m2 or less. Patients with bulimia nervosa (and some patients with anorexia nervosa) engage in uncontrollable binge-eating episodes, followed by purging behaviours such as self-induced vomiting or the use of laxatives. Dermatological features associated with purging behaviours include:
- Calluses over the knuckles (also called Russell sign) caused by repeated rubbing of the skin against the upper front teeth when the hand is used to induce vomiting.
- Erosion of dental enamel and tooth loss due to vomiting.
- Post-vomiting facial petechiae – tiny red, purple, or brown spots due to breakage of small blood vessels and bleeding into the skin.
- Post-vomiting subconjunctival haemorrhage – red eye/s due to damage to small blood vessels in the eyes.
- Adverse reactions to drugs such as laxatives, diuretics, and appetite suppressants e.g. thiazide diuretics may induce drug photosensitivity.
Diagnosis of malnutrition
- Progressive weight loss; children may have poor growth.
- Blood tests may reveal low levels of protein; electrolyte imbalances (abnormal levels of salts in the blood); and evidence of iron deficiency or vitamin deficiencies.
In patients with severe malnutrition, fluid and electrolyte imbalances should be corrected first. Food should be introduced slowly and carefully. Vitamin and mineral supplements may be needed. The skin changes associated with malnutrition generally resolve when nutritional deficiencies are corrected and the patient gains weight.
- Strumia R. Dermatologic signs in patients with eating disorders. Am J Clin Dermatol. 2005;6(3):165-73.
- Tyler I, Wiseman MC, Crawford RI, Birmingham CL. Cutaneous manifestations of eating disorders. J Cutan Med Surg. 2002 Jul-Aug;6(4):345-53. Epub 2002 Apr 15. Review.
- Protein-Energy Malnutrition – eMedicine Dermatology
- Malnutrition – eMedicine Pediatrics: General Medicine
On DermNet NZ:
- Medscape Reference
- Eating Disorders – MedlinePlus
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