From the Guidelines
Severe anorexia nervosa can lead to generalized pruritus through malnutrition, causing essential fatty acid deficiency, decreased sebum production, protein deficiency, vitamin deficiencies, hormonal imbalances, dehydration, and liver dysfunction. The primary mechanism involves malnutrition, which leads to a deficiency in omega-3 and omega-6 fatty acids, crucial for maintaining skin barrier function, resulting in dry, scaly skin (xerosis) that becomes increasingly itchy 1. Additionally, anorexia often results in:
- Decreased sebum production, further contributing to skin dryness
- Protein deficiency, impairing skin repair and regeneration
- Vitamin deficiencies (especially vitamins A, B, C, and E), compromising skin integrity and immune function
- Hormonal imbalances, including reduced estrogen and thyroid hormone levels, affecting skin health
- Dehydration, concentrating waste products in the skin that can trigger itching
- Liver dysfunction, leading to cholestasis and elevated bile salts in the bloodstream, depositing in the skin and causing intense itching
Treatment of generalized pruritus in severe anorexia nervosa requires a comprehensive approach, focusing on nutritional rehabilitation and addressing the underlying eating disorder, as recommended by the American Psychiatric Association 1. This includes individualized goals for weekly weight gain and target weight, eating disorder-focused psychotherapy, and nutritional expertise to restore skin health and overall well-being.
From the Research
Mechanism of Severe Anorexia Nervosa Leading to Generalized Pruritis
- Severe anorexia nervosa can lead to generalized pruritis due to various factors, including psychopathology, endocrine factors, regional blood flow variation, eczema, and the role of central opioid and serotonergic activity 2.
- A study found that 58% of women with severe anorexia nervosa suffered from pruritus at low weight, and the severity of pruritus was significantly associated with changes in body mass index 2.
- Pruritus in anorexia nervosa may be related to zinc deficiency, which is common in patients with eating disorders 3, 4.
- Zinc deficiency can lead to overactivation and upregulation of NMDA receptors, resulting in pathologically high levels of glutamate, calcium influx, and subsequent excitotoxicity, which can disrupt synaptogenesis and synaptic plasticity 4.
- Generalized pruritus is a common skin manifestation in anorexia nervosa, occurring in 16.6% of patients in one study 5.
- The exact mechanism of generalized pruritis in anorexia nervosa is not fully understood, but it is thought to be a complex interplay of psychological, hormonal, and nutritional factors 6, 3, 2, 5.
Skin Manifestations in Anorexia Nervosa
- Skin signs are prevalent among patients with anorexia nervosa, including xerosis, hair effluvium, nail changes, cheilitis, acne, gingivitis, acrocyanosis, diffuse hypertrichosis, carotenoderma, generalized pruritus, hyperpigmentation, striae distensae, factitial dermatitis, seborrheic dermatitis, poor wound healing, melasma, and Russell's sign 3, 5.
- The frequency and type of skin manifestations may vary depending on the type of anorexia nervosa, with some signs being more common in the restrictive type and others in the bulimic type 5.
- Weight restoration and improvement in body mass index can lead to improvement in some skin signs, such as xerosis, cheilitis, acrocyanosis, hyperpigmentation, and acne 5.