Clip When taking the health history the patient complains of pruritus what is a common cause of this symptom? ?
Kinh Nghiệm về When taking the health history the patient complains of pruritus what is a common cause of this symptom? Mới Nhất
Hoàng Thị Bích Ngọc đang tìm kiếm từ khóa When taking the health history the patient complains of pruritus what is a common cause of this symptom? được Cập Nhật vào lúc : 2022-10-06 14:35:28 . Với phương châm chia sẻ Bí quyết Hướng dẫn trong nội dung bài viết một cách Chi Tiết Mới Nhất. Nếu sau khi đọc nội dung bài viết vẫn ko hiểu thì hoàn toàn có thể lại Comment ở cuối bài để Ad lý giải và hướng dẫn lại nha.Itching is a symptom that can cause significant discomfort and is one of the most common reasons for consultation with a dermatologist. Itching leads to scratching, which can cause inflammation, skin degradation, and possible secondary infection. The skin can become lichenified, scaly, and excoriated.
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Itch can be prompted by diverse stimuli, including light touch, vibration, and wool fibers. There are a number of chemical mediators as well as different mechanisms by which the sensation of itch occurs. Specific peripheral sensory neurons mediate the itch sensation. These neurons are distinct from those that respond to light touch or pain; they contain a receptor, MrgA3, the stimulation of which causes the sensation of itching.
Histamine is the well-known mediator. It is synthesized and stored in mast cells in the skin and is released in response to various stimuli. Other mediators (eg, neuropeptides) can either cause the release of histamine or act as pruritogens themselves, thus explaining why antihistamines ameliorate some cases of itching and not others. Opioids have a central pruritic action as well as stimulating the peripherally mediated histamine itch.
There are 4 mechanisms of itch:
Systemic: This mechanism is related to diseases of organs other than skin (eg, cholestasis).
Psychogenic: This mechanism is related to psychiatric conditions.
Intense itching stimulates vigorous scratching, which in turn can cause secondary skin conditions (eg, inflammation, excoriation, infection), which can lead to more itching through disruption of the skin barrier. Although scratching can temporarily reduce the sensation of itch by activating inhibitory neuronal circuits, it also leads to amplification of itching the level of the brain, exacerbating the itch–scratch cycle.
Itching can be a symptom of a primary skin disease or, less commonly, a systemic disease. Also, drugs can cause itching (see see Table: Some Causes of Itching Some Causes of Itching ).
Many skin disorders cause itching. The most common include
In systemic disorders, itching may occur with or without skin lesions. However, when itching is prominent without any identifiable skin lesions, systemic disorders and drugs should be considered more strongly. Systemic disorders are less often a cause of itching than skin disorders, but some of the more common causes include
Cholestasis
Less common systemic causes of itching include hyperthyroidism Hyperthyroidism Hyperthyroidism is characterized by hypermetabolism and elevated serum levels of không lấy phí thyroid hormones. Symptoms include palpitations, fatigue, weight loss, heat intolerance, anxiety, and tremor... read more , hypothyroidism Hypothyroidism Hypothyroidism is thyroid hormone deficiency. Symptoms include cold intolerance, fatigue, and weight gain. Signs may include a typical facial appearance, hoarse slow speech, and dry skin. Diagnosis... read more , diabetes Diabetes Mellitus (DM) Diabetes mellitus is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia. Early symptoms are related to hyperglycemia and include polydipsia... read more , iron deficiency, dermatitis herpetiformis Dermatitis Herpetiformis Dermatitis herpetiformis is an intensely pruritic, chronic, autoimmune, papulovesicular cutaneous eruption strongly associated with celiac disease. Typical findings are clusters of intensely... read more , and polycythemia vera Polycythemia Vera Polycythemia vera is a chronic myeloproliferative neoplasm characterized by an increase in morphologically normal red cells (its hallmark), but also white cells and platelets. Ten to 15% of... read more .
History of present illness should determine onset of itching, initial location, course, duration, patterns of itching (eg, nocturnal or diurnal, intermittent or persistent, seasonal variation), and whether any rash is present. A careful drug history should be obtained including both prescription and over-the-counter medications with particular attention paid to recently started drugs. The patient's use of moisturizers and other topicals (eg, hydrocortisone, diphenhydramine) should be reviewed. History should include any factors that make the itching better or worse.
Review of systems should seek symptoms of causative disorders, including
Constitutional symptoms of weight loss, fatigue, and night sweats (cancer)
Past medical history should identify known causative disorders (eg, renal disease, cholestatic disorder, cancer being treated with chemotherapy) and the patient’s emotional state. Social history should focus on family members with similar itching and skin symptoms (eg, scabies, pediculosis); relationship of itching to occupation or exposures to plants, animals, or chemicals; and history of recent travel.
Physical examination begins with a review of clinical appearance for signs of jaundice, weight loss or gain, and fatigue. Close examination of the skin should be done, taking note of presence, morphology, extent, and distribution of lesions. Cutaneous examination also should make note of signs of secondary infection (eg, erythema, swelling, warmth, yellow or honey-colored crusting).
The examination should make note of significant adenopathy suggestive of cancer. Abdominal examination should focus on organomegaly, masses, and tenderness (cholestatic disorder or cancer). Neurologic examination should focus on weakness, spasticity, or numbness (multiple sclerosis).
The following findings are of particular concern:
Constitutional symptoms of weight loss, fatigue, and night sweats
Extremity weakness, numbness, or tingling
Abdominal pain and jaundice
Urinary frequency, excessive thirst, and weight loss
Generalized itching that begins shortly after use of a drug is likely caused by that drug. Localized itching (often with rash) that occurs in the area of contact with a substance is likely caused by that substance. However, many systemic allergies can be difficult to identify because patients typically have consumed multiple different foods and have been in contact with many substances before developing itching. Similarly, identifying a drug cause in a patient taking several drugs may be difficult. Sometimes the patient has been taking the offending drug for months or even years before developing a reaction.
In the minority of patients in whom no skin lesions are evident, a systemic disorder should be considered. Some disorders that cause itching are readily apparent on evaluation (eg, chronic renal failure, cholestatic jaundice). Other systemic disorders that cause itching are suggested by findings ( see Table: Some Causes of Itching Some Causes of Itching ). Rarely, itching is the first manifestation of significant systemic disorders (eg, polycythemia vera, certain cancers, hyperthyroidism).
Many dermatologic disorders are diagnosed clinically. However, when itching is accompanied by discrete skin lesions of uncertain etiology, biopsy can be appropriate. When an allergic reaction is suspected but the substance is unknown, skin testing (either prick or patch testing depending on suspected etiology) is often done. When a systemic disorder is suspected, testing is directed by the suspected cause and usually involves complete blood count; liver, renal, and thyroid function measurements; and appropriate evaluation for underlying cancer.
Local skin care
Topical treatment
Systemic treatment
Itching due to any cause benefits from use of cool or lukewarm (but not hot) water when bathing, mild or moisturizing soap, limited bathing duration and frequency, frequent lubrication, humidification of dry air, and avoidance of irritating clothing. Avoidance of contact irritants (eg, wool clothing) also may be helpful.
Topical drugs may help localized itching. Options include lotions or creams that contain camphor and/or menthol, pramoxine, capsaicin, or corticosteroids. Corticosteroids are effective in relieving itch caused by inflammation but should be avoided for conditions that have no evidence of inflammation. Topical benzocaine, diphenhydramine, and doxepin should be avoided because they may sensitize the skin.
Systemic drugs are indicated for generalized itching or local itching resistant to topical agents. Antihistamines, most notably hydroxyzine, are effective, especially for nocturnal itch, and are most commonly used. Sedating antihistamines must be used cautiously in older patients during the day because they can lead to falls; newer nonsedating antihistamines such as loratadine, fexofenadine, and cetirizine can be useful for daytime itching. Other drugs include doxepin (typically taken night due to high level of sedation), cholestyramine (for renal failure, cholestasis, and polycythemia vera), opioid antagonists such as naltrexone (for biliary pruritus), and possibly gabapentin (for uremic pruritus).
Physical agents that may be effective for itching include ultraviolet phototherapy.
Age-related changes in the immune system and in nerve fibers may contribute to the high prevalence of itch in older adults.
Xerotic eczema is very common among older patients. It is especially likely if itching is primarily on the lower extremities.
Severe, diffuse itching in older patients should raise concern for cancer, especially if another etiology is not immediately apparent.
When treating older patients, sedation can be a significant problem with antihistamines, so dose reduction may be appropriate. Use of nonsedating antihistamines during the day and sedating antihistamines night, liberal use of topical ointments and corticosteroids (when appropriate), and consideration of ultraviolet phototherapy can help avoid the complications of sedation.
Itching is usually a symptom of a skin disorder or systemic allergic reaction but can result from a systemic disorder.
If skin lesions are not evident, systemic causes should be investigated.
Skin care (eg, limiting bathing, avoiding irritants, moisturizing regularly, humidifying environment) should be observed.
Symptoms can be relieved by topical or systemic drugs.
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