Pruritus (ie, itching) is one of the most common symptoms of patients with dermatologic disorders. Itch receptors are unmyeli-nated, penicillate (ie, brushlike) nerve endings that are found ex-clusively in the skin, mucous membranes, and cornea. Although pruritus is usually caused by primary skin disease with resultant rash or lesions, it may occur without a rash or lesion. This is re-ferred to as essential pruritus, which generally has a rapid onset, may be severe, and interferes with normal daily activities.
Pruritus may be the first indication of a systemic internal dis-ease such as diabetes mellitus, blood disorders, or cancer. It may also accompany renal, hepatic, and thyroid diseases (Chart 56-2). Some common oral medications such as aspirin, antibiotics, hor-mones (ie, estrogens, testosterone, or oral contraceptives), and opioids (ie, morphine or cocaine) may cause pruritus directly or by increasing sensitivity to ultraviolet light. Certain soaps and chemicals, radiation therapy, prickly heat (ie, miliaria), and con-tact with woolen garments are also associated with pruritus. Pru-ritus may also be caused by psychological factors, such as excessive stress in family or work situations.
Scratching the itchy area causes the inflamed cells and nerve end-ings to release histamine, which produces more pruritus, gener-ating a vicious itchâ€“scratch cycle. If the patient responds to an itch by scratching, the integrity of the skin may be altered, and excoriation, redness, raised areas (ie, wheals), infection, or changes in pigmentation may result. Pruritus usually is more severe at night and is less frequently reported during waking hours, prob-ably because the person is distracted by daily activities. At night, when there are few distractions, the slightest pruritus cannot be easily ignored. Severe itching is debilitating.
Pruritus occurs frequently in elderly people as a result of dry skin. Elderly people are also more likely to have a systemic illness that triggers pruritus, are at higher risk for occult malignancy, and are more likely to be on multiple medications than is the younger population. All of these factors increase the incidence of pruritus.
A thorough history and physical examination usually provide clues to the underlying cause of the pruritus, such as hay fever, allergy, recent administration of a new medication, or a change of cos-metics or soaps. After the cause has been identified, treatment of the condition should relieve the pruritus. Signs of infection and environmental clues, such as warm, dry air or irritating bed linens, should be identified. In general, washing with soap and hot water is avoided.
Bath oils (eg, Lubath, Alpha-Keri) containing a sur-factant that makes the oil mix with bath water may be sufficient for cleaning. However, an elderly patient or a patient with un-steady balance should avoid adding oil because it increases the danger of slipping in the bathtub. A warm bath with a mild soap followed by application of a bland emollient to moist skin can control xerosis (ie, dry skin). Applying a cold compress, ice cube, or cool agents that contain menthol and camphor (which constrict blood vessels) may also help relieve pruritus.
Topical corticosteroids may be beneficial as anti-inflammatory agents to decrease itching. Oral antihistamines are even more ef-fective because they can overcome the effects of histamine release from damaged mast cells. An antihistamine, such as diphenhy-dramine (Benadryl) or hydroxyzine (Atarax), prescribed in a seda-tive dose at bedtime is effective in producing a restful and comfortable sleep.
Nonsedating antihistamine medications such as fexofenadine (Allegra) should be used to relieve daytime pru-ritus. Tricyclic antidepressants, such as doxepin (Sinequan), may be prescribed for pruritus of neuropsychogenic origin. If pruritus continues, further investigation of a systemic problem is advised.
The nurse reinforces the reasons for the prescribed therapeutic regimen and counsels the patient on specific points of care. If baths have been prescribed, the patient is reminded to use tepid (not hot) water and to shake off the excess water and blot between intertriginous areas (ie, body folds) with a towel. Rubbing vigor-ously with the towel is avoided because this overstimulates the skin and causes more itching. It also removes water from the stra-tum corneum. Immediately after bathing, the skin should be lu-bricated with an emollient to trap moisture.
The patient is instructed to avoid situations that cause va-sodilation (ie, expansion of the blood vessels). Examples include exposure to an overly warm environment and ingestion of alco-hol or hot foods and liquids. All can induce or intensify itching. Using a humidifier is helpful if environmental air is dry. Activi-ties that result in perspiration should be limited because perspi-ration may irritate and promote pruritus. If the patient is troubled at night with itching that interferes with sleep, the nurse can advise wearing cotton clothing next to the skin rather than synthetic materials. The room should be kept cool and humidi-fied. Vigorous scratching should be avoided, and nails kept trimmed to prevent skin damage and infection. When the un-derlying cause of pruritus is unknown and further testing is re-quired, the nurse explains each test and the expected outcome.
Pruritus of the genital and anal regions may be caused by small particles of fecal material lodged in the perianal crevices or attached to anal hairs or by perianal skin damage caused by scratching, moisture, and decreased skin resistance as a result of corticosteroid or antibiotic therapy. Other possible causes of peri-anal itching include local irritants such as scabies and lice, local lesions such as hemorrhoids, fungal or yeast infections, and pin-worm infestation. Conditions such as diabetes mellitus, anemia, hyperthyroidism, and pregnancy may also result in pruritus. Occasionally, no cause can be identified.
The patient is instructed to follow proper hygiene measures and to discontinue home and over-the-counter remedies. The per-ineal or anal area should be rinsed with lukewarm water and blot-ted dry with cotton balls. Premoistened tissues may be used after defecation. Cornstarch can be applied in the skinfold areas to ab-sorb perspiration.
As part of health teaching, the nurse instructs the patient to avoid bathing in water that is too hot and to avoid using bubble baths, sodium bicarbonate, and detergent soaps, all of which ag-gravate dryness. To keep the perineal or perianal skin area as dry as possible, patients should avoid wearing underwear made of synthetic fabrics. Local anesthetic agents should not be used be-cause of possible allergic effects. The patient should also avoid vasodilating agents or stimulants (eg, alcohol, caffeine) and me-chanical irritants such as rough or woolen clothing. A diet that includes adequate fiber may help maintain soft stools and prevent minor trauma to the anal mucosa.