Urticaria
Urticaria is a vascular skin reaction characterized by the eruption of transient pruritic wheals — smooth, slightly elevated patches with well-defined erythematous margins and pale centers of various shapes and sizes (hives). It’s produced by the local release of histamine or other vasoactive substances as part of a hypersensitivity reaction. (See Recognizing common skin lesions, pages 302 and 303.)
Acute urticaria evolves rapidly and usually has a detectable cause, commonly hypersensitivity to certain drugs, foods, insect bites, inhalants, or contactants. Emotional stress or environmental factors may also trigger urticaria. Although individual lesions usually subside within 12 to 24 hours, new crops of lesions may erupt continuously, thus prolonging the attack.
Urticaria lasting longer than 6 weeks is classified as chronic. The lesions may recur for months or years, and the underlying cause is usually unknown. Occasionally, a diagnosis of psychogenic urticaria is made.
Angioedema, or giant urticaria, is characterized by the acute eruption of wheals involving the mucous membranes and, occasionally, the arms, legs, or genitals.
Act Now: In an acute case of urticaria, quickly evaluate the patient’s respiratory status and take his vital signs. Ensure patent I.V. access if you note respiratory difficulty or signs of impending anaphylactic shock. Also, as appropriate, give local epinephrine or apply ice to the affected site to decrease absorption through vasoconstriction. Clear and maintain the patient’s airway, give oxygen as needed, and institute cardiac monitoring. Have resuscitation equipment at hand, and be prepared to begin cardiopulmonary resuscitation. Intubation or a tracheostomy may be required.
Assessment
History
If the patient isn’t in distress, obtain his medical history. Does he have known allergies? Does urticaria follow a seasonal pattern? Do certain foods or drugs seem to aggravate it? Is there a relationship to physical exertion? Is the patient routinely exposed to chemicals on the job or at home? Has the patient recently changed or used new skin products? Obtain a detailed drug history, including prescription and over-the-counter drugs. Note a history of chronic or parasitic infection, skin disease, or GI disorder.
Physical examination
Obtain the patient’s vital signs. Perform a complete cardiopulmonary assessment, noting signs and symptoms of shock or respiratory distress. Assess for urticaria in other areas because new crops may continue to appear.
Pediatric pointers
Pediatric forms of urticaria include acute papular urticaria (usually after insect bites) and urticaria pigmentosa (rare). Hereditary angioedema may be causative.
Medical causes
Anaphylaxis
An acute reaction, anaphylaxis is marked by the rapid eruption of diffuse urticaria and angioedema, with wheals ranging from pinpoint to palm-size or larger. Lesions are usually pruritic and stinging; paresthesia commonly precedes their eruption. Other acute findings include profound anxiety, weakness, diaphoresis, sneezing, shortness of breath, profuse rhinorrhea, nasal congestion, dysphagia, and warm, moist skin.
Hereditary angioedema
An autosomal dominant disorder, cutaneous involvement is manifested by nonpitting, nonpruritic edema of an extremity or the face. Respiratory mucosal involvement can produce life-threatening acute laryngeal edema.
Lyme disease
Although not diagnostic of this tick-borne disease, urticaria may result from the characteristic skin lesion (erythema chronicum migrans). Later effects include constant malaise and fatigue, intermittent headache, fever, chills, lymphadenopathy, neurologic and cardiac abnormalities, and arthritis.
Other causes
Drugs
Many drugs can cause urticaria; the most common include aspirin, atropine, codeine, dextran, immune serums, insulin, morphine, penicillin, quinine, sulfonamides, and vaccines. In addition, radiographic contrast medium commonly produces urticaria, especially when administered intravenously.
Nursing considerations
To help relieve the patient’s discomfort, apply a bland skin emollient or one containing menthol and phenol. Expect to give an antihistamine, a systemic corticosteroid or, if stress is a suspected contributing factor, a tranquilizer. Tepid baths and cool compresses may also enhance vasoconstriction and decrease pruritus.
Patient teaching
Teach the patient to avoid the causative stimulus, if appropriate. Emphasize the importance of wearing a medical alert bracelet that identifies his allergies. Explain the risks of delayed symptoms and which signs and symptoms to report. Discuss methods and techniques to prevent anaphylaxis. Instruct the patient on the proper use of an anaphylaxis kit and epinephrine administration.
Pictures
Book Source Details
- Book Title: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series
- Author(s): Springhouse
- Year of Publication: 2007
- Copyright Details: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, Copyright © 2007 Lippincott Williams & Wilkins.
Other Book Chapters Related to Hives
Read excerpts from these other book chapters related to Hives:
Medical Books Excerpts
- Urticaria
- "In A Page: Pediatric Signs and Symptoms" (2007)
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- Urticaria
- "A Pocket Manual of Differential Diagnosis" (1999)
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- Pustular rash
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
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- Urticaria
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
- Urticaria
- "Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series" (2007)
- [ read ]
- Urticaria
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
Copyright Details: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, Copyright © 2008 Williams & Wilkins.
More About Causes of Hives
» Next page: Pustular rash (Signs & Symptoms: A 2-in-1 Reference for Nurses)
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