Itching is a symptom that can cause considerable discomfort, and one of the most common reasons for consulting a dermatologist. Itching leads to scratching, which can cause inflammation, skin damage and a possible secondary infection. The skin can lichenified, scaly, and his scuffed.

(See also judgment of dermatological patients.) Itching is a symptom that can cause considerable discomfort, and one of the most common reasons for consulting a dermatologist. Itching leads to scratching, which can cause inflammation, skin damage and a possible secondary infection. The skin can lichenified, scaly, and his scuffed. Pathophysiology itching can be caused by various stimuli, for example by light touch, vibration, and wool fibers. There are a number of chemical mediators and various mechanisms by which the feeling of itching occurs. The existence of specific peripheral sensory neurons that are responsible for transmitting the itch, has recently been demonstrated. These neurons are different from those that respond to light touch or pain; they contain a receptor MrgA3 whose stimulation evokes the sensation of itching. Mediators Histamine is one of the major mediators. It is synthesized in mast cells in the skin and stored and released in response to various stimuli. Other mediators (z. B. neuropeptides) can either cause the release of histamine or act independently as a trigger of the itching, which explains why antihistamines improve some cases of itching and others do not. Opioids are central pruritic activity and the stimulation of the peripherally mediated Histaminjuckreizes.Mechanismen There are four mechanisms of itch: Dermatologic – usually caused by inflammatory or pathological processes (eg, urticaria, eczema.) Systemic – associated with diseases of other organs than the skin (. eg cholestasis) Neuropathic – based on diseases of the CNS or peripheral nervous system Psychogenic (e.g., multiple sclerosis.) – related to psychiatric disorders Intense itching animated to vigorous scratching, leading to secondary skin diseases ( z. B. inflammation, excoriation, infection), which may lead to more itching caused by destruction of the Hautbarrire. Although scratching can temporarily reduce the feeling of itching by activating inhibitory neural circuits, it also leads to the reinforcement of the itching at the level of the brain, which aggravates the itch-scratch-circle. Etiology itching can be a symptom of a primary skin disease or, rarely, a systemic disease. Even drugs can cause itching (see Some causes of itching). Skin Many skin diseases cause itching. Among the most common dry skin include atopic dermatitis (eczema) Contact dermatitis skin infections caused by fungi Systemic diseases In systemic diseases itching can occur with or without skin lesions. If the itching is, however, difficult, and no obvious skin lesions, systemic diseases and drugs should be examined more closely. Systemic diseases are less frequent compared to skin diseases a cause itching, but some of the more common causes include allergic reaction (eg. As compared to food, medicines and bites and stings) cholestasis Chronic kidney disease include Less common systemic causes of itching hyperthyroidism, hypothyroidism, diabetes, iron deficiency, dermatitis herpetiformis and polycythemia vera.Medikamente medications can itch as an allergic reaction or by direct triggering of histamine release cause (usually morphine, some iv contrast media). Some causes of itching Cause Suggestive Findings Diagnostic Approach Primary skin disease atopic dermatitis presence of erythema, possible lichenification, lichen pilaris, xerosis, Dennie-Morgan fold, hyper linear Palmae generally will have a family history of atopy or chronically recurring dermatitis Clinical Evaluation contact dermatitis dermatitis secondary to contact allergens; Erythema, vesicles Clinical evaluation Dermatophytosis (. Eg tinea capitis, tinea corporis, tinea cruris, tinea pedis) Localized itching, circular lesions with raised scaly borders areas with alopecia Common sites are the genital area and feet in adults; Scalp and body in children Sometimes favorable factors (eg., Moisture, obesity) potassium hydroxide examination of Läsionsgeschabsel Lichen simplex Chronicus areas of skin thickening secondary to repeated scratching the lesions are discrete, erythematous, scaly plaques that well-defined, rough, lichenification skin Clinical Rating pediculosis Common sites are the scalp, armpits, waist and pubic areas of excoriation, possible punctate lesions from fresh bites, possible bilateral blepharitis inspecting the eggs (nits), and sometimes lice Psoriasis is not necessarily limited plaques with silvery scales usually on the extensor surfaces of the elbows, knees, scalp and torso itching plaques might arthritis manifests in the joints as stiffness and pain Clinical evaluation scabies Small erythematous or dark papules at one end of a fine, wavy , slightly scaly line of up to 1 cm in length (gear); may Intensive on network areas, the waistline, the flexures and the areola in women and the genitals in men family or close acquaintances with similar symptoms of nocturnal itching Clinical evaluation Microscopic examination of skin scrapings of corridors urticaria Vanishing, limited, elevated, erythematous lesions with central pallor Can acute or chronic (? 6 weeks). Clinical evaluation xerosis (dry skin) The most common in winter Itchy, dry, scaly skin, usually on the lower limbs aggravated by dry heat clinical evaluation Systemic diseases Allergic reaction, internal (many captured substances) itching, rash with maculae and papules or urticaria may or may not have a known allergy try to avoid Sometimes prick tests cancer (z. B. Hodgkin’s Lymphoma hom, polycythemia vera, Mycosis fungoides) Itching may any other symptom preceded by burning up itching, (especially in the lower extremities Hodgkin’s lymphoma) itch after bathing (polycythemia vera) Heterogeneous skin lesions – plaque, stains, tumors, erythroderma (Mycosis fungoides ) blood smear radiograph of the chest biopsy (bone marrow in polycythemia vera, Hodgkin’s lymphoma in lymphatic glands, skin lesion in mycosis fungoides) cholestasis findings that indicate liver or gallbladder damage or malfunction (eg. B. jaundice, steatorrhea, fatigue, pain in the right upper quadrant) Usually extensive itching without a rash, sometimes develops in late pregnancy liver function tests and evaluation of the cause of jaundice diabetes * Frequent urination, thirst, weight loss, vision changes urine and blood sugar A1C iron deficiency anemia fatigue, headaches, irritability, exercise intolerance, Pica, thinning hair hemoglobin, hematocrit, red cell indices, ferritin, iron and iron-binding capacity Multiple sclerosis sporadic severe itching, numbness, tingling in the extremities, optic neuritis, vision loss, spasticity or weakness, dizziness GRF MRI analysis Evoked Potentials Psychiatric disorders linear excoriations, presence of a psychiatric disease (e.g.. As clinical depression, delusional parasitosis) Clinical evaluation diagnosis of exclusion kidney disease stage renal disease itching, can be worse during dialysis can occur mainly on the back diagnosis of exclusion thyroid disease * weight loss, palpitations, sweating, irritability (hyperthyroidism ) weight gain, depression, dry skin and hair (hypothyroidism) TSH, T4 drugs Medications (eg. As opioids, penicillin, ACE inhibitors, statins, antimalarials, epidermal growth factor inhibitors, interleukin 2, vemurafenib, ipilimumab, other cytostatics) History taking Physical examination * itch than to be seen complaints of the patient is unusual. HbA1C = glycosylated hemoglobin; KOH = potassium hydroxide; T4 = thyroxine, TSH = thyroid stimulating hormone. Judgment history history of present illness should determine (nocturnal or diurnal, intermittent or persistent, seasonality z. B.) as well as the presence of rash onset of itching, original location, history, time pattern of pruritus. A careful drug history should be available that includes both prescription and OTC drugs, with special attention to medications, of which began taking recently. The use of moisturizers and other medicines for external application (eg., Hydrocortisone, diphenhydramine) in patients should be verified. The history should include all factors that make the itching better or worse. A review of organ systems should investigate symptoms of the causative diseases, including irritability, sweating, weight loss, and palpitations (hyperthyroidism) depression, dry skin and weight gain (hypothyroidism) headache, Pica, thinning hair and exercise intolerance (iron deficiency anemia) general symptoms such as weight loss, fatigue and night sweats (cancer) Temporary weakness, numbness, tingling and blurred vision or vision loss (multiple sclerosis) steatorrhea, jaundice and right upper quadrant pain (cholestasis) Frequent urination, excessive thirst and weight loss (diabetes) history of previous drug should (known causative diseases such . B. kidney disease, cholestatic disease, cancer chemotherapy treatment) and the emotional state of the patient identifizi older. The social history should cover family members with similar itch-and skin symptoms (such as scabies, pediculosis.); the relationship between itching and occupation or exposure to plants, animals or chemicals; and the history of recent travels konzentrieren.Körperliche examination The physical examination begins with a review of the clinical appearance for signs of jaundice, weight loss or weight gain, and fatigue. A close examination of the skin should be carried out to detect the presence, morphology, size and distribution of the lesions. A skin analysis should also identify evidence of a secondary infection (z. B. erythema, swelling, heat, yellow or honey-colored crusting). The investigation should hold significant gland diseases, which indicate cancer. An examination of the abdomen should focus on organomegaly, quantities, and sensitivity (cholestatic disease or cancer). A neurological examination should konzentrieren.Warnzeichen on weakness, spasticity or numbness (multiple sclerosis) The following results are of particular importance: general symptoms such as weight loss, fatigue and night sweats weakness in the extremities, numbness or tingling abdominal pain and jaundice Frequent urination, excessive thirst and weight loss interpreting the results generalized itching, which begins shortly after the use of a drug is most likely caused by this drug. Localized itching (often with rash), which occurs in the area of ??contact with a substance which is probably caused by this substance. However, many systemic allergies may be difficult to identify because the patients have consumed several different foods in general, and came into contact with many substances before the itching developed. Similarly, the identification of a drug can be difficult as the cause, if the patient is taking multiple medications. Sometimes the patient takes the drug for months or even years before a reaction develops. When an etiology is not immediately apparent, appearance and location of skin lesions may suggest a diagnosis (see table: Some causes of itching). In the minority of patients in whom no skin lesions are evident, a systemic disease should be considered. Some diseases that cause itching, are easily recognizable in the evaluation (chronic z. B. kidney failure, cholestatic jaundice). Other systemic disorders that cause itching, are indicated by the findings (see Table: Some causes of itching). Rare Itching is the first manifestation of significant systemic diseases (eg. As polycythemia vera, certain cancers, hyperthyroidism) .Tests Many dermatological disorders are clinically diagnosed. If the itching is accompanied by discrete skin lesions of unknown etiology, a biopsy may be appropriate. If an allergic reaction is suspected, but the substance is unknown, often carried out (depending on the suspected etiology either skin prick test or patch test) skin tests. On suspicion of a systemic disease, the tests are focused on the suspected cause, and usually include a complete blood count; Liver function tests, kidney function and thyroid parameters; and appropriate investigations for underlying cancer. Each treatment underlying condition is treated. Supportive treatment includes the following (also see table: Some therapeutic approaches to itching): Local Skin Care Topical treatment Systemic treatment skincare itching can be due to any cause by cold or lukewarm (not hot) water when bathing, mild or moisturizing soap, limited bath life and – reduce recurrence, frequent creaming, humidification of dry air, and avoid irritating or tight clothing. Avoiding irritants (eg. As woolen clothing) can also be helpful sein.Topische drugs In localized itching are often topical medications are effective. Options include lotions or creams that camphor and / or menthol, pramoxine, capsaicin or corticosteroids included. Corticosteroids are effective in relieving itching caused by inflammation, but should be avoided if there are no signs of inflammation. Topical benzocaine, diphenhydramine and doxepin should be avoided as they sensitize the skin können.Systemische drugs In generalized or local itching that does not respond to topical agents, systemic drugs are indicated. Antihistamines, particularly hydroxyzine, are effective, especially in nocturnal itching, and are most commonly used. Sedating antihistamines should be used with caution in elderly patients during the day, as they can lead to falls; newer non-sedating antihistamines such as loratadine, fexofenadine and cetirizine, can be helpful for itching during the day. Other drugs are doxepin (taken because of the high degree of sedation usually at night), cholestyramine (renal failure, cholestasis and polycythemia vera), opioid antagonists such as naltrexone (with biliary pruritus) and possibly gabapentin (for uremic pruritus). Physical agents that may be effective against pruritus include UV phototherapy. Some therapeutic approaches to itching drug / agent Ordinary cure explanations Topical Treatment capsaicin cream Can Apply regularly for the required period of time to a place with neuropathic itching ? 2 weeks required for the effect of vegetable oil can help in removing an initial burning sensation dissipates with time corticosteroid creams or ointments on the betroffe Apply nen area twice a day for 5-7 days Avoid the face, moisten skin folds should not be used for long periods (> 2 weeks) menthol-containing and / or camphor-containing creams Apply to affected areas as needed for relief This will have preparations can pramoxine foam apply strong odors daily as needed 4-6 times dryness or irritation at the application site cause tacrolimus ointment or pimecrolimus cream on d are en affected area Should Apply twice daily for 10 days for extended periods or in children used <2 years Ultraviolet B therapy 1-3 times per week until the itching subsides The treatment is often continued for months sunburn-like side effects can occur long-term risk of skin cancer, including melanoma Systemic treatment cetirizine * 5-10 mg po 1 times a day can rarely a sedative effect in elderly patients have cholestyramine (cholestatic pruritus) 4-16 g p.o. 1 times daily Compliance may be low constipating, impalpable Can taking other drugs affect cyproheptadine † 4 mg p.o. 3 times daily sedative, also helpful if given before bedtime diphenhydramine † 25-50 mg po every 4-6 h (no more than 6 doses within 24 h) sedating, also helpful if given before bedtime doxepin 25 mg p.o. 1 times a day Helpful Very sedative for severe and chronic itching, so before bedtime take fexofenadine 60 mg po * 2 times daily headaches can be a side effect of gabapentin (uraemic pruritus) 100 mg po after hemodialysis The sedative effect can be a problem at the beginning and low doses to clinical effect titrated hydroxyzine † 25-50 mg p.o. every 4-6 h (no more than 6 doses within 24 h) sedating, also helpful if * 10 mg p.o. before bedtime given loratadine 1 times daily Rarely can a sedative effect in elderly patients occur naltrexone (cholestatic pruritus) 12.5-50 mg po 1 times a day Can result in patients with tolerance to opioids withdrawal symptoms * Non-sedating antihistamines. † Sedative antihistamines. Geriatrics Basics Age-related changes in the immune system and nerve fibers may contribute to the high prevalence of itching in older adults. Xerotic eczema are very common in the elderly. It is particularly likely if the itching is primarily due to the lower extremities. Severe, diffuse itching in the elderly should be cause for concern about cancer, especially if another cause is not immediately apparent. In the treatment of the elderly, the sedative effect of antihistamines can be a significant problem. The use of non-sedating antihistamines during the day and sedating antihistamines at night, liberal use of topical ointments and corticosteroids (if applicable), and the inclusion of UV phototherapy can help to avoid the complications of sedation. Summary itching is usually a symptom of a disease of the skin or systemic allergic reaction, but can result from a systemic disease. If lesions are not visible, the causes should be investigated. Skin care (eg. As limited bathing, avoiding irritants, regular moisturizing, humidification of the environment) must be observed. The symptoms can be alleviated by topical or systemic medications.


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