Understanding How Liver Damage Causes Itching: Mechanisms and Treatment

Itching or pruritus, particularly associated with liver damage, is primarily linked to the accumulation of certain substances in the bloodstream due to impaired liver function. Here are the key mechanisms involved:

Bile Salt Accumulation

The breakdown and absorption of fats rely on the production of bile by the liver. In liver damage such as cirrhosis or cholestasis, bile salts can accumulate in the bloodstream, leading to itching. High levels of bile salts are thought to irritate nerve endings in the skin leading to itching.

Histamine Release

Liver dysfunction can affect the metabolism of various substances, including histamine. Increased histamine levels can contribute to pruritus, as histamine is a well-known mediator of itching.

Altered Hormone Levels

Liver damage can disrupt the metabolism of hormones and other compounds, potentially leading to changes in the levels of substances that modulate itching and skin health.

Inflammatory Mediators

Liver disease can lead to systemic inflammation, resulting in the release of pro-inflammatory cytokines that may contribute to itching.

Uremic Toxins

In severe cases of liver damage leading to hepatic failure, the buildup of toxins that are normally cleared by the liver can also cause pruritus.

Itching or pruritus associated with liver damage arises from a build-up of bile in the skin, a yellowish-green fluid produced by the liver and stored in the gallbladder. If the liver is damaged, it may not process bile effectively, leading to a skin buildup that causes itching.

Prevalence of Itching in Liver Illness

Itching appears in 20-70% of patients with liver diseases, with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and intrahepatic cholestasis of pregnancy (ICP) being the most common causes. However, in alcohol-related liver diseases and nonalcoholic fatty liver disease, itching is rare.

Probable Causes of Itching

Various factors have been identified as potential causes of itching in liver disease:

Bile salts: Some patients may have higher levels of bile salts under the skin, causing itching even if histamine levels are normal. Histamine: Elevated histamine levels can contribute to itching, but antihistamines are often not effective in treating pruritus. Serotonin (5-hydroxytryptamine): Changes in serotonin may alter itch perception, with selective serotonin reuptake inhibitors (SSRIs) sometimes helping manage itchiness. Female sex hormones: Female sex hormones can worsen itching during pregnancy or hormone replacement therapy. Alkaline enzyme ALP Lysophosphatidic acid (LPA) and autotaxin

Itching associated with liver disease does not typically improve on its own. Treatment involves a combination of therapies, and success varies depending on the underlying cause. Here are some strategies to alleviate itching:

Preventing Skin Irritation and Itching

Avoid scratching to prevent skin damage and infection. Keep nails short to reduce the risk of breaking the skin while scratching. Avoid hot water and prolonged exposure to heat or sunlight. Choose gentle, fragrance-free soaps and moisturizers. Apply cold compresses to alleviate the urge to scratch. Avoid irritants and use protective measures like gloves. Wear loose, breathable clothing and use a humidifier during the dry winter months.

Medical Treatments

Drugs and medical treatments may be necessary, including:

Bile salt sequestrants: Cholestyramine can remove bile salts from circulation. Rifampicin: Inhibits bile acids and needs regular monitoring due to potential side effects. Naltrexone: Blocks opioid effects and requires regular monitoring. Sertraline (Zoloft): An SSRI that can manage chronic itch.

Antihistamines, phototherapy, and liver transplants may also be considered depending on the severity of the condition.

It is important to consult a healthcare provider if itching persists, as it can significantly affect sleep, quality of life, and contribute to other health issues such as insomnia, fatigue, anxiety, and depression.