Pruritus

Definition

Pruritus is an unpleasant, irritating sensation that provokes the desire to scratch. It is a common symptom associated with various medical conditions and can significantly impact a person's quality of life.

5 Must Know Facts For Your Next Test

1. Pruritus is a common side effect associated with the use of opioid agonists, as these medications can activate the release of histamine and other pruritogenic mediators.
2. Bile acid sequestrants, such as cholestyramine and colestipol, can cause pruritus as a result of their ability to disrupt the enterohepatic circulation of bile acids.
3. Fibrates, a class of lipid-lowering medications, have been known to induce pruritus in some patients, particularly during the initial stages of treatment.
4. Niacin (vitamin B3) can also trigger pruritus, especially when administered in high doses, due to its vasodilatory effects and the release of histamine.
5. Effective management of pruritus may involve the use of antihistamines, topical corticosteroids, or other targeted therapies, depending on the underlying cause.

Review Questions

• Explain how pruritus is related to the use of opioid agonists.
  • Opioid agonists, such as morphine and codeine, can induce pruritus as a common side effect. This is because these medications can activate the release of histamine and other pruritogenic mediators, which stimulate the itch receptors in the skin. The activation of these receptors leads to the unpleasant sensation of pruritus, prompting the desire to scratch. Understanding this relationship is important when prescribing opioid agonists and managing their potential side effects.
• Describe the mechanism by which bile acid sequestrants can cause pruritus.
  • Bile acid sequestrants, such as cholestyramine and colestipol, are used to lower cholesterol levels by binding to bile acids in the intestine and preventing their reabsorption. However, this disruption of the enterohepatic circulation of bile acids can lead to an accumulation of bile acids in the skin, which can stimulate the itch receptors and cause pruritus. This is an important consideration when prescribing bile acid sequestrants, as the management of pruritus may be necessary to ensure patient comfort and adherence to the medication regimen.
• Evaluate the role of niacin (vitamin B3) in the development of pruritus and discuss the potential strategies for managing this side effect.
  • Niacin, a B-complex vitamin commonly used to treat high cholesterol, can trigger pruritus as a side effect, particularly when administered in high doses. This is due to niacin's vasodilatory effects, which can lead to the release of histamine and the subsequent stimulation of itch receptors in the skin. To manage pruritus associated with niacin therapy, healthcare providers may consider strategies such as starting with a low dose of niacin and gradually titrating the dosage, using antihistamines or topical corticosteroids to alleviate the symptoms, or exploring alternative lipid-lowering medications that are less likely to cause pruritus. By understanding the relationship between niacin and pruritus, healthcare providers can optimize the management of high cholesterol while minimizing the impact on the patient's quality of life.

Related terms

Itch: A sensation that triggers the urge to scratch, often described as a tickling, tingling, or burning feeling on the skin.

Dermatitis: Inflammation of the skin, which can lead to pruritus and other skin-related symptoms.

Histamine:

A chemical released by the body's immune system that can trigger the sensation of pruritus and other allergic reactions.