Introduction
Chronic pruritus without an underlying dermatosis is a diagnostically challenging presentation that is frequently encountered in general practice. It refers to an itch persisting for more than 6 weeks without a rash. When no underlying cause is identified following appropriate assessment, it is classified as chronic pruritus of unknown origin (CPUO). CPUO can significantly impact quality of life (QoL), contributing to anxiety, inattention, and sexual dysfunction.1 This article outlines how GPs can assess and manage such patients.
What are the key features of clinical assessment for chronic pruritus without a dermatosis?
A detailed history is important to identify the cause of chronic pruritus without a dermatosis. In general practice, most cases are benign, relating to xerosis, medication-induced itch, psychogenic pruritus, age-related (senile) pruritus, or idiopathic itch. Idiopathic pruritus accounts for approximately 50% of presentations.2 Although uncommon, chronic pruritus without a dermatosis may be the presenting feature of an underlying systemic disease (Box 1).
Box 1. Differential diagnosis for chronic pruritus without an underlying dermatosis Xerosis and senile pruritus often present with dry, scaly skin that worsens in cold, low-humidity environments or with frequent use of soap. A detailed medication history is important, as many prescribed or illicit drugs can induce pruritus. Opioids may cause chronic generalised itch, while stimulants such as amphetamines can contribute to psychogenic pruritus.3 Certain medications, including corticosteroids, may mask the underlying dermatosis, such as in scabies, delaying diagnosis. Although scabies presents with a characteristic rash, it may be subtle,2 and pruritus can persist after successful management.
A systems review and mental health assessment should be performed to identify systemic and psychogenic causes. Systemic symptoms, such as fever, night sweats, weight loss, or fatigue, may suggest malignancy, liver, renal, endocrine, or haematological disease. Psychogenic pruritus may fluctuate with anxiety or other psychosocial stressors. A history of crawling sensation may reflect delusional parasitosis.2 The history should also explore the distribution, triggers, and temporal pattern of pruritus.4 Pruritus following water exposure may suggest aquagenic pruritus, which is associated with polycythaemia vera.5 Localised pruritus may reflect a neuropathic cause such as brachioradial pruritus.4
Social history should address diet and malabsorption risks, as nutrient deficiencies (for example, iron) may contribute to pruritus.4,5 Travel history and assessing risk factors for communicable disease can help identify infectious causes, such as strongyloidiasis or hepatitis.4
Examination
The examination should begin with a thorough head-to-toe skin inspection, identifying primary lesions that may indicate a specific dermatological condition. The scalp, mucosae, intertriginous areas, genitalia, web spaces, and nails should be assessed as they may reveal diagnostic clues and are often overlooked. Dermographism and xerosis should also be assessed. Urticaria and dermographism cause transient wheals that may not be evident during examination unless specifically assessed, mimicking chronic pruritus without a dermatosis. Secondary skin changes, such as superficial erosions, scratch marks, lichenification, prurigo nodularis, and scarring, may result from chronic scratching and should be distinguished from primary lesions.
If primary lesions are absent, the examination should involve identifying signs of systemic causes of pruritus (Box 1).
What are the differential diagnoses for chronic pruritus without a dermatosis?
The differential diagnoses can be categorised into dermatological, systemic, neuropathic, and psychogenic causes.1 These are summarised in Box 1.
What is the initial management of chronic pruritus without a dermatosis in the primary care setting?
When a cause is identified or suspected, it should be investigated if appropriate and managed accordingly. In the absence of a clear aetiology, a stepwise management approach should be initiated before pursuing investigations.
General measures include avoiding factors that dry or irritate the skin, such as hot showers, excessive washing, and low-humidity environments.6 Patients should be advised to use lukewarm water, apply emollients daily (particularly after showering), wear soft, breathable clothing (for example, cotton), and apply cool compresses to minimise scratching.6 Medications suspected of causing pruritus should be discontinued for several weeks to assess for improvement.2 If pruritus persists despite these measures, screening blood tests should be performed to identify potential systemic causes.
A trial of non-sedating antihistamines, such as fexofenadine 180 mg, loratadine 10 mg, or cetirizine 10 mg (mildly sedating), for 4 weeks may be considered for symptomatic relief.2,6,7 The dose may be increased up to four times the standard dose if required and discontinued if ineffective.2
Short-term use of topical corticosteroids is advised for managing secondary inflammatory lesions/lichenification caused by chronic pruritus.7 It should not be used for managing pruritus without inflammatory lesions.7
Referral to secondary care should be considered if red-flag symptoms are present, including unintentional weight loss, lymphadenopathy, or other systemic symptoms.
Further guidance on the management of pruritus without a rash can be accessed from the websites of the Primary Care Dermatology Society and the British Association of Dermatologists:
What investigations should be considered for chronic pruritus without a dermatosis in the primary care setting?
Initial screening blood tests include full blood count, liver and renal function tests, glycated haemoglobin, fasting glucose, thyroid function tests, and iron studies.4,6 Further investigations should be guided by history and examination findings,4 and are indicated when screening results are abnormal, red-flag symptoms are present, or a secondary cause is suspected. Serum calcium, phosphate, parathyroid hormone, and vitamin B12 or D may be considered if endocrine disorders or nutrient deficiencies are suspected.4,7
When liver function tests, relevant risk factors, or clinical features suggest an autoimmune or hepatobiliary cause, antinuclear, antimitochondrial, anti-smooth muscle, anti-liver kidney microsomal, anti-soluble liver antigen, and perinuclear antineutrophil cytoplasmic antibodies should be considered.7 A bile acid test should be arranged in pregnant patients with pruritus to exclude intrahepatic cholestasis of pregnancy.7 Infectious causes are important to consider. HIV or viral hepatitis serology are indicated in patients with relevant risk factors.7 Parasitic screening (stool microscopy, skin snip biopsy, or skin scraping) may be appropriate for those with a travel history or features suggestive of strongyloidiasis, schistosomiasis, scabies, or onchocerciasis.
Malignancy screening should be considered in patients with severe and persistent pruritus within the first 3 months when history, examination, and initial investigations fail to identify a cause.2 In such cases, CT imaging of the neck, chest, abdomen, and pelvis may be warranted.2 Early haematology involvement is recommended when a haematological cause is suspected. GPs may initiate targeted investigations when clinically indicated. Serum and urine protein electrophoresis can be ordered to assess for multiple myeloma.7
Skin biopsy has a limited role but should be performed if invisible mycosis fungoides or non-bullous pemphigoid is suspected. If pruritus is associated with neurological symptoms, further assessment may be indicated and is often guided by neurology.
When no underlying cause is identified following appropriate assessment, a diagnosis of idiopathic CPUO may be made.
How can CPUO be managed in the primary care setting?
Treatment of CPUO in primary care should focus on alleviating symptoms and improving QoL. Patients should continue with general measures as outlined previously and trial a non-sedating antihistamine.5 Patients should be reviewed frequently and referred to dermatology if there is uncertainty with diagnosis or symptoms persist despite management.5 Regular review is important as pruritus may precede the diagnosis of systemic or malignant diseases such as Hodgkin lymphoma, even when initial investigations are unremarkable.
Dermatology may offer further non-pharmacological and pharmacological interventions. Phototherapy with ultraviolet B is a non-pharmacological therapy that can be helpful in patients with CPUO and systemic causes of pruritus.5,8
Pharmacological therapy can be categorised into topical and systemic treatment. Topical therapies for CPUO include coolants (phenol and menthol), local anaesthetics, antihistamine (doxepin), and cannabinoids.5,8 Topical cannabinoids have been used for CPUO; however, more studies are required to evaluate their safety and effectiveness.8 Systemic treatments for CPUO have limited evidence on safety and efficacy, with publications mostly limited to case reports and series.5 Medications that could provide benefit include GABAergic agents, non-sedating antihistamines, antidepressants (tricyclic antidepressants and serotonin reuptake inhibitors), κ-opioid agonists, μ-opioid antagonists, and immunosuppressants.5,8 However, immunosuppressants are not commonly used for idiopathic itch. Systemic treatments can be considered under specialist supervision but are not typically initiated in primary care.
Emerging therapies for CPUO include neurokinin-1 receptor antagonists, biologics, and Janus kinase inhibitors.8
Summary
Chronic pruritus without a dermatosis has a broad differential diagnosis and requires a systematic approach. Despite a thorough assessment at presentation, no underlying cause may be identified. In such cases, symptomatic management and ongoing surveillance are required.
Notes
Competing interests
The authors have declared no competing interests.
- Received September 5, 2025.
- Revision received October 30, 2025.
- Accepted November 11, 2025.
- © British Journal of General Practice 2026
