From the Guidelines
Pruritus should be managed by addressing the underlying cause, and for patients with generalized pruritus without an underlying dermatosis, a thorough history and physical examination should be performed, along with initial investigations including full blood count, blood film, lactate dehydrogenase, and erythrocyte sedimentation rate, as recommended by the British Association of Dermatologists' guidelines 1. When evaluating a patient with pruritus, it is essential to consider various potential underlying causes, including hematological, endocrinological, and neurological conditions.
- For patients with suspected hematological involvement, initial investigations should include full blood count, blood film, lactate dehydrogenase, and erythrocyte sedimentation rate, as well as consideration of immunoglobulins and urinary paraproteins 1.
- In cases of polycythemia vera (PV), the Janus kinase (JAK)2 V617F mutation should be analyzed, and secondary causes of polycythaemia should be investigated if the mutation is absent 1.
- For pruritus associated with PV, treatment options may include aspirin, interferon alpha therapy, or selective serotonin reuptake inhibitors, with interferon alpha being a recommended treatment for intractable pruritus 1. Key considerations in managing pruritus include:
- Identifying and addressing the underlying cause
- Performing a thorough history and physical examination
- Conducting initial investigations to rule out potential underlying conditions
- Considering treatment options based on the underlying cause, such as aspirin or interferon alpha for PV-associated pruritus
- Providing symptomatic relief with antihistamines, moisturizing lotions, or topical steroids as needed.
From the Research
Definition and Prevalence of Pruritus
- Pruritus, defined as itch experienced for 6 weeks or longer, affects approximately 22% of people in their lifetime 2.
- Approximately 1% of physician visits are for the chief concern of chronic pruritus 2.
Etiology of Pruritus
- Chronic pruritus can be categorized by etiology into inflammatory, neuropathic, or a combination of inflammatory and neuropathic pruritus 2.
- Chronic pruritus is due to inflammation in approximately 60% of patients and may be caused by eczema, psoriasis, or seborrheic dermatitis 2.
- Chronic pruritus is due to a neuropathic or mixed etiology in approximately 25% of patients 2.
- Neuropathic causes of chronic pruritus include postherpetic neuralgia and notalgia paresthetica and are typically due to localized or generalized nerve dysregulation 2.
Diagnosis of Pruritus
- A thorough history, review of symptoms, and laboratory evaluation should be performed, particularly for people with chronic pruritus lasting less than 1 year 2.
- Clinicians should consider the following tests: complete blood cell count, complete metabolic panel, and thyroid function testing to evaluate for hematologic malignancy, liver disease, kidney disease, or thyroid disease 2.
- An exposure history may reveal symptom triggers, and a thorough skin examination is essential 3.
- Primary skin lesions indicate diseased skin, and secondary lesions are reactive and result from skin manipulation, such as scratching 3.
Treatment of Pruritus
- First-line treatment for inflammatory chronic pruritus includes topical anti-inflammatory therapies such as hydrocortisone (2.5%), triamcinolone (0.1%), or tacrolimus ointment 2.
- Approximately 10% of patients do not respond to topical therapies, and referral to dermatology and systemic oral or injectable treatments such as dupilumab or methotrexate may be considered 2.
- Neuropathic topical treatments such as menthol, pramoxine, or lidocaine can be used either alone or in combination with immunomodulatory agents such as topical steroids 2.
- Other effective therapies for neuropathic pruritus include gabapentin, antidepressants such as sertraline or doxepin, or opioid receptor agonist/antagonists such as naltrexone or butorphanol 2.