bubble_chart Overview

Cutaneous pruritus (pruritus) is one of the common skin diseases in clinical practice, especially prevalent among the elderly. It is characterized primarily by cutaneous pruritus without primary lesions. Clinically, it can be divided into localized and generalized types.

bubble_chart Etiology

Cutaneous pruritus is a subjective symptom that occurs on the skin and induces scratching. Its causes are relatively complex, with disease factors including internal or external causes, or both.

1. Internal causes: Mostly lead to generalized cutaneous pruritus.

(1) Visceral diseases: Functional or organic diseases of internal organs such as the stomach, intestines, liver, and kidneys, especially in patients with diabetes, uremia, or liver diseases, often result in generalized cutaneous pruritus. Certain tumors, such as leukemia, lymphoma, Hodgkin's disease, mycosis fungoides, and cervical malignancy with cachexia, can also cause cutaneous pruritus.

(2) Neurological and psychiatric disorders: Conditions like cerebral arteriosclerosis, tabes dorsalis, and neurasthenia may lead to generalized or localized cutaneous pruritus. Clinically, it is common for patients with neurological dysfunction to experience certain hallucinations, believing there are insects in their skin and feeling itchy, some even developing a habit of scratching.

(3) Endocrine disorders: Some women often experience cutaneous pruritus during pregnancy, which generally disappears after childbirth. Menstrual irregularities or ovarian diseases frequently cause vulvar cutaneous pruritus. Pruritus in the elderly may be related to decreased levels of sex hormones in the body. Patients with thyroid diseases may also exhibit cutaneous pruritus.

In addition to the above, infections in focal areas, medications, diet (alcohol abuse), food allergies, and infections by Chinese Taxillus Herb insects or fungi can all lead to generalized or localized cutaneous pruritus.

2. External causes: Can induce generalized or localized cutaneous pruritus. Changes in temperature often trigger cutaneous pruritus, with patients suffering from winter pruritus or summer pruritus being extremely sensitive to temperature variations. Overheated bedding, sudden exposure to heat or cold may all provoke episodes of cutaneous pruritus.

Mechanical friction or stimulation by physical and chemical factors can cause localized cutaneous pruritus. For example, some people are sensitive to wool, overly alkaline soaps, or wearing synthetic fiber textiles.

Additionally, irritants such as disinfectants, insecticides, deodorants, and dyes can all cause localized skin itching.

bubble_chart Clinical Manifestations

Based on the extent of cutaneous pruritus, the disease is classified as generalized or localized.

1. Generalized cutaneous pruritus (pruritus universalis): Patients experience itching sensations all over the body, though not simultaneously; the itching often shifts from one area to another. The severity varies—some may tolerate the itch, while others feel intense itching, resorting to scrubbing the skin with an iron brush or scalding hot water until bleeding occurs, with pain and burning pain temporarily relieving the itch. The itching is often worse at night, leading to insomnia or disturbed sleep. Due to intense cutaneous pruritus and constant scratching, scratch marks, blood crusts, linear abrasions, eczema-like changes, lichenification, or pigmentation may appear. The scratched skin is also prone to infection, leading to boils or folliculitis.

Senile cutaneous pruritus occurs in the elderly, often with the torso being the itchiest. Winter cutaneous pruritus appears in cold seasons, triggered by cold. Patients often experience intense cutaneous pruritus on the inner thighs, calves, and other areas when undressing for bed, leading to a vicious cycle of scratching until local bleeding occurs.

2. Localized cutaneous pruritus is clinically most common in the anus, vulva, and scrotum.

(1) Anal cutaneous pruritus: The most common localized form, often seen in middle-aged men, typically confined to the perianal area, sometimes extending forward to the scrotum or backward to the gluteal cleft. Women and children with enterobiasis may also develop it. The perianal skin often appears grayish-white or pale due to maceration, with thickened anal folds and radial rhagades from scratching. Secondary infections may occur, and prolonged scratching can lead to lichenification and pigmentation.

(2) Vulvar cutaneous pruritus: Primarily affects the labia majora and minora, but may also involve the mons pubis and clitoris. Constant scratching thickens the vulvar skin, causing grayish-white maceration, with redness, swelling, and erosion of the clitoris and vaginal mucosa.

(3) Scrotal cutaneous pruritus: Itching occurs on the scrotum but may extend to the penis or anus. Persistent scratching thickens the scrotal skin, causing pigmentation changes, lichenification, or eczema-like lesions, including erosion, exudation, and crusting.

bubble_chart Treatment Measures

Since the disease cause of this condition is relatively complex, it is essential to carefully inquire about the medical history, identify and eliminate the disease cause to achieve a根治, thereby attaining the goal of relieving itching. Otherwise, cutaneous pruritus cannot be completely eradicated.

Treat diabetes, nephritis, and liver diseases. If anal or vulvar cutaneous pruritus is present, investigate whether it is due to infections such as intestinal Chinese Taxillus Herb worms, fungi, or trichomonads, and apply appropriate killing worms and antifungal medications. Chronic cutaneous pruritus of unknown cause is often related to diet and情绪. Some patients may need to alter their diet or abstain from alcohol to alleviate cutaneous pruritus. Patients under精神紧张 should maintain a cheerful mood and ensure adequate rest.

1. Internal Medication Treatment

(1) Application of Antihistamines In addition to chlorpheniramine, cyproheptadine, and promethazine, other options include astemizole (10mg once daily), terfenadine (60mg twice daily), acrivastine (8mg 2-3 times daily), and cetirizine (10mg once daily).

(2) For systemic cutaneous pruritus, intravenous procaine hydrochloride封闭 can be used. Intravenous procaine infusion should last at least half an hour, with procaine dosage calculated at 4mg per kilogram of body weight, dissolved in生理盐水 to form a 0.1% concentration, administered once daily for 10 sessions as one course. For localized cutaneous pruritus, triamcinolone acetonide (10mg) can be injected intralesionally once weekly, or dexamethasone (2mg) can be injected intralesionally 1-2 times weekly.

(3) Senile cutaneous pruritus can be treated with sex hormones. Male patients may receive testosterone propionate (50-100mg) via intramuscular injection 1-2 times weekly, or methyltestosterone (10mg) three times daily. Female patients may take diethylstilbestrol (0.5mg) three times monthly. Sex hormone therapy should be avoided or used cautiously in patients with生殖系统 tumors or肝肾功能不全.

(4) For systemic cutaneous pruritus, intravenous injection of 10% calcium gluconate or 10% sodium thiosulfate can be administered. Vitamin C may also be given intravenously or via drip.

(5) For severe cutaneous pruritus that affects sleep, sedatives or hypnotics can be used as appropriate based on the condition.

(6) Chinese medicine Chinese medicinals treatment Chinese medicine attributes acute cutaneous pruritus to wind, dampness, and heat, thus adopting清热去风 as the treatment principle, often using Jingfang Qingre Decoction. For慢性病人, aside from cases caused by wind, dampness, and heat, many are due to blood deficiency producing wind or blood stasis qi stagnation. Therefore, the treatment principles involve nourishing blood to dispel wind or nourishing blood to dispel wind while活血化淤, employing Yong'an止痒方,痒疹方, or血燥方. For scrotal cutaneous pruritus and vulvar cutaneous pruritus, Chinese medicine often attributes these to liver-gallbladder dampness-heat, with Gentian Liver-Draining Decoction yielding较好效果.

2. Topical Medication Treatment The goal of topical medication is to relieve or减轻 cutaneous pruritus. Common topical agents often contain carbolic acid, menthol,麝香草酚, or coal tar solution as antipruritics, formulated into lotions, creams, etc., based on the condition. Commonly used options include calamine lotion or phenol calamine lotion (calamine lotion with 1%麝香草酚 or 1% menthol). Corticosteroid ointments or creams may also be used. For vulvar cutaneous pruritus or anal cutaneous pruritus, avoid medications containing irritants.

bubble_chart Differentiation

The diagnosis of this disease is based on generalized or localized cutaneous pruritus without primary skin lesions, only secondary rashes, and generally is not difficult. However, it sometimes needs to be differentiated from the following diseases.

1. Scabies Although it also presents with intense nocturnal cutaneous pruritus, there are papules, vesicles, burrows, and nodules on the scrotum, penis, or labia majora. There is often a family history of simultaneous onset, and scabies mites can be detected locally.

2. Scrotal eczema Sometimes it is difficult to differentiate. A careful review of the medical history may reveal an acute eczema process, with papules, vesicle exudation, and crusting, while lichenification is not very obvious.