Overview
This podcast episode features Dr. Daniel Butler discussing the definition, evaluation, causes, and management strategies for chronic pruritus, with practical guidance for general clinicians and dermatologists.
Definition and Epidemiology
- Chronic pruritus is defined as itching that lasts more than six weeks.
- It accounts for about 1% of all physician visits and is often underdiagnosed.
- It is the most common symptom leading patients over age 50 to see a dermatologist.
Main Categories of Pruritus
- Pruritus is divided into inflammatory, neuropathic, and mixed types.
- Inflammatory pruritus typically presents with visible rashes, such as eczema, psoriasis, or infectious causes like scabies.
- Neuropathic pruritus results from nerve dysfunction or impingement, common examples include notalgia paresthetica and brachioradial pruritus.
- Systemic diseases like diabetes can cause more diffuse neuropathic pruritus.
Clinical Evaluation Approach
- Initial assessment should distinguish between pruritus with and without a visible rash.
- Rash presence suggests an inflammatory or infectious etiology; absence may indicate neuropathic or subclinical inflammatory causes.
- Systematic history-taking includes inquiring about nerve-related conditions and past rashes, even if not present during the exam.
Laboratory Workup
- Recommended baseline tests for pruritus without rash (duration <1 year): CBC with differential, CMP, and TSH.
- Laboratory tests help identify systemic or subclinical causes including hematologic, hepatic, renal, or thyroid disorders.
Treatment Strategies
- First-line therapy for inflammatory pruritus: topical steroids (hydrocortisone 2.5% or triamcinolone 0.1%), applied with appropriate follow-up.
- Rapid improvement (within 1–2 weeks) is expected for inflammatory pruritus; lack of response should prompt diagnostic reconsideration.
- Second-line options include phototherapy or targeted biologics (e.g., dupilumab, tralokinumab).
- Neuropathic pruritus first-line therapy: topical anesthetics like lidocaine, menthol, or pramoxine, often available over-the-counter.
- Second-line neuropathic treatments: oral agents such as gabapentin or pregabalin.
Referral to Dermatology
- Refer when diagnosis is uncertain, skin biopsy is needed, advanced systemic workup is indicated, or for third-line pharmacologic management.
- Consider referral if uncomfortable with any treatment step or medication.
Recommendations / Advice
- Approach chronic pruritus systematically and avoid dismissing cases without a visible rash.
- Ensure follow-up after initiating therapy to assess efficacy and revisit the diagnosis if no improvement.
- Use over-the-counter neuropathic treatments consistently for up to three months to assess benefit.
Action Items
- TBD – Clinicians: Order baseline labs (CBC, CMP, TSH) for chronic pruritus cases without rash and symptoms under one year.
- TBD – Clinicians: Arrange follow-up after initiating topical steroid treatment for inflammatory pruritus.
- TBD – Clinicians: Refer to dermatology for uncertain diagnoses, need for biopsy, advanced workup, or complex medication management.