OVERVIEW

What is pruritus?

Pruritus is a skin condition characterized by itching without primary skin lesions (though secondary lesions may occur due to scratching).

The causes are diverse, including dry skin, underlying diseases, allergies, psychological factors, medications, and climate changes. In addition to itching, patients may experience burning or crawling sensations. Persistent scratching can lead to skin lesions such as excoriations, scabs, hyperpigmentation, or hypopigmentation.

Treatment focuses on addressing the underlying cause and symptom relief. Severe itching may be managed with topical or systemic medications.

In daily life, patients should actively treat underlying conditions and avoid potential triggers to prevent recurrence.

Is pruritus common in daily life?

Pruritus is frequently seen in dermatology clinics, particularly among the elderly. With age, sebum production declines, leading to skin atrophy, dryness, and scaling, which can trigger itching^[1]. Epidemiological studies show a prevalence of 12% in outpatient seniors aged 65 and 20% in those over 85^[2].

What are the types of pruritus?

Based on affected areas, it is classified into:

• Generalized pruritus: Widespread itching not limited to specific body parts, including senile pruritus, systemic disease-related (e.g., diabetes, kidney disease, cholestasis, thyroid disorders), seasonal (winter/summer), and pregnancy-related pruritus.
• Localized pruritus: Itching confined to specific areas like anal, vulvar, or scrotal pruritus^[3].

Is pruritus contagious?

No, it is not contagious. However, the condition tends to recur, so preventive measures are important.

SYMPTOMS

What are the symptoms of pruritus?

The characteristic feature of this condition is the absence of primary skin lesions, with only symptoms of skin itching. It may be accompanied by sensations such as burning or crawling. Scratching can lead to secondary skin lesions, such as excoriations, blood crusts, hyperpigmentation or hypopigmentation^[4], and even lichenification or secondary skin infections.

Skin itching can affect the entire body or localized areas, with specific manifestations as follows:

• Generalized pruritus: Itching sensations occur all over the body without a fixed location, usually not simultaneously but shifting from one area to another. The intensity of itching varies, often presenting as episodic and worsening at night. Some patients may scratch intensely until they feel pain or burning to relieve the itch. The duration of itching also varies, ranging from a few minutes to several hours.
• Localized pruritus: Intense episodic itching in specific areas, commonly occurring in the genital region, anus, lower legs, scalp, etc.^[5].

CAUSES

What are the causes of pruritus?

The etiology of pruritus is relatively complex:

• Dry skin: The most common cause of generalized pruritus^[5]. As sweat and sebaceous glands atrophy and degenerate with age, the elderly are more prone to dry skin, leading to pruritus. Additionally, frequent use of soap or other alkaline products for bathing, excessively hot water, or dry air can also cause dry skin.
• Disease factors: Conditions such as kidney disease, diabetes, hyperthyroidism or hypothyroidism, lymphoma, uremia, biliary cirrhosis, and Sjögren's syndrome may trigger generalized pruritus. Endocrine disorders in women, trichomoniasis, gonorrhea, and other conditions can cause vulvar itching, while hemorrhoids, anal fissures, or pinworm infections may lead to anal itching^[5].
• Psychological factors: Negative emotions like anxiety, obsessive-compulsive disorder, depression, or emotional tension, if not properly managed, can heighten sensitivity to itching and contribute to pruritus.
• Allergic factors: Consumption of allergenic foods or exposure to allergens like pollen may induce pruritus.
• Medication factors: Drugs such as analgesics, vitamin B, ACE inhibitors, or sulfonamides may cause pruritus due to immune dysfunction altering drug metabolism^[6].
• Lifestyle factors: Use of highly alkaline soaps, cleansing cosmetics (facial cleansers, exfoliants, etc.), exposure to disinfectants, pesticides, or wearing synthetic fabrics can irritate the skin and trigger itching. Poor hygiene in living or working environments may also contribute to skin itching.
• Climate changes: Cold, dry winters reducing skin moisture or excessive sweating in hot summers can both lead to pruritus.

DIAGNOSIS

How do doctors diagnose pruritus?

It is usually diagnosed based on characteristic manifestations (itching without primary skin lesions), but the specific cause needs to be identified through physical examination and other laboratory tests.

What tests are needed for pruritus?

• Blood tests: Including complete blood count, liver and kidney function, thyroid hormones, blood glucose levels, C-reactive protein, erythrocyte sedimentation rate (ESR), thyroid-stimulating hormone (TSH), and tumor markers. These help screen for potential causes of pruritus. Note that fasting is required for blood glucose and liver/kidney function tests.
• Vaginal secretion examination: Female patients with vulvar itching should undergo this test to check for conditions like vaginitis.
• Intestinal examination: Patients with anal itching may need a digital rectal exam or colonoscopy to rule out hemorrhoids or tumors.
• Stool examination: For anal itching, a stool test may be performed to check for parasites or eggs.
• Allergen testing: If allergies are suspected, allergen testing can help identify or rule out triggers.

If necessary, a tissue biopsy, X-ray, CT scan, or other imaging tests may be conducted to clarify the cause.

What diseases can pruritus be confused with?

• Scabies: Both cause intense itching, but scabies presents with blisters, pustules, or papules, distinguishable by skin lesions.
• Neurodermatitis: Both involve scratching-induced marks or scabs, but neurodermatitis shows immediate lichenification after scratching.
• Lichen simplex chronicus: Both cause severe itching, but lichen simplex chronicus presents with one or more reddish papules.
• Chronic eczema: Both involve intense itching, but chronic eczema includes papules, erythema, or blisters.
• Insect bite dermatitis: Both may show scratch marks, but insect bite dermatitis has a history of bites and features edema, erythema, or blisters.

TREATMENT

Which department should I visit for pruritus?

Pruritus is generally treated in the dermatology and venereology department.

How is pruritus treated?

Treatment for pruritus includes general therapy, medication, and physical therapy:

General Therapy

• Identify the underlying cause of pruritus as soon as possible and treat accordingly. For example, if itching is caused by diabetes, blood sugar levels should be actively controlled to alleviate symptoms.
• Advise elderly patients to avoid scratching as much as possible to prevent further damage to the skin barrier and worsening the itch-scratch cycle.

Medication

1. Topical treatments:

   • Antipruritics: Help relieve itching symptoms, such as ethanol preparations containing menthol or camphor, calamine lotion, or capsaicin. However, capsaicin may cause a brief burning sensation during use^[7].
   • Topical anesthetics: Such as pramoxine, which numbs the skin surface to block nerve signals and alleviate itching.
   • Calcineurin inhibitors: Such as pimecrolimus or tacrolimus, which can reduce skin itching.
   • Topical corticosteroids: Such as dexamethasone ointment or hydrocortisone butyrate cream, which can relieve itching when applied locally^[4]. However, due to side effects, they should only be used short-term and are not recommended for elderly patients^[8].

2. Systemic medications:

   • Antihistamines: Such as loratadine or ketotifen fumarate, which can reduce itching symptoms.
   • Opioid receptor antagonists: Such as naltrexone or naloxone, used for itching caused by cholestasis or uremia. However, these drugs have significant side effects like nausea, vomiting, and sleep disturbances and must be used strictly as prescribed.
   • Antiepileptic drugs: Such as gabapentin or pregabalin, which have anti-anxiety and sedative effects and can relieve itching caused by psychological factors.
   • 5-HT receptor antagonists: Such as ondansetron or cyproheptadine, which can alleviate itching from chronic kidney failure or cholestasis.
   • Antidepressants: Such as doxepin or mirtazapine, which can help control itching^[8].

Physical Therapy
Ultraviolet therapy: UV irradiation has antibacterial and anti-inflammatory effects, helping to relieve skin itching. It is effective for certain types of pruritus, such as that caused by uremia or psychological factors^[8].

DIET & LIFESTYLE

What should patients with pruritus pay attention to in their diet?

• Maintain balanced nutrition, avoid spicy foods to prevent skin irritation, and consume plenty of fresh vegetables and fruits.
• Avoid alcohol, strong tea, and smoking to prevent worsening the condition.
• Minimize intake of allergenic foods such as fresh shrimp, fish, and shellfish.

What should pruritus patients pay attention to in daily life?

• Wear loose-fitting cotton clothing and maintain personal hygiene.
• Avoid excessively hot water when bathing, use mild cleansing products, and apply ample moisturizer immediately after bathing.
• Ensure indoor air isn't too dry; use a humidifier if necessary.
• Avoid contact with irritants or allergens like wool or synthetic fabrics.
• Seek active treatment, avoid excessive scratching, and never wash with soapy hot water.
• Stress and anxiety can worsen itching—manage these emotions through meditation or communication.
• Get sufficient sleep to reduce skin sensitivity.

PREVENTION

Can Pruritus Be Prevented? How to Prevent It?

• Controlling underlying conditions that cause pruritus and avoiding potential triggers can help prevent the disease to some extent.
• Patients with underlying diseases should actively treat and manage their symptoms.
• Develop good habits, maintain skin hydration and hygiene, and avoid using overly harsh cleansing products.
• Avoid exposure to allergens like pollen and refrain from using wool or synthetic fiber products.
• Engage in moderate exercise to promote skin metabolism and reduce dryness.
• Maintain a relaxed mood and avoid irritability, tension, or anxiety.
• Prevent weather-related skin itching—change clothes promptly if overheated or sweaty, and use moisturizers in cold, dry conditions.