allerg

Sickle Cell Information Center Protocols

Edited by James Eckman, M.D. and Allan Platt, PA-C

Allergic Reactions

The manifestations of allergic reactions vary in severity from mild fever, rash, pruritus, urticaria (hives), to life threatening problems or angioneurotic edema, respiratory failure, and anaphylaxis with shock. Such reactions can occur after exposure to drugs, contrast material, serums, vaccines, local anesthetic agents, cosmetics, insect bites, and foods.

History may have to be delayed until after treatment is initiated in severe reactions.

Clinical Findings

Subjective Data

Present Illness. Note onset of symptoms, itching, rash, swelling in throat, difficulty breathing, apprehension, weakness, syncopy. Document present medications, food, recent insect bites, outdoor activities,or other known exposure.

Past Medical History. Document prior allergic history, medications and agents and exposures known to cause problems, past response to therapy, and family atopic history.

Review of Symptoms. Exclude prior cardiac or respiratory difficulty

Objective data

Physical Examination.

- General. Respiratory distress, stridor, pallor, altered mental status.

- Vital Signs. Pulse, blood pressure (supine/upright), respiratory rate, temperature.

- HEENT. Orbital edema, edema of uvula, soft palate, posterior pharynx. Voice, difficulty swallowing, stridor.

- Chest. Prolonged expiratory phase, wheezing, rales.

- Heart. Cardiac rate and rhythm. Murmur or S3.

Skin. Cyanosis, edema, erythematous, papular rash, vesicles, urticaria.

Laboratory

- Minimum Lab. None in acute, life-threatening allergic reactions.

- Additional Lab. CBC with differential, reticulocyte and platelet count looking for eosinophilia and hemoconcentration. Urinalysis for protein, Chem Pannel, blood gases with respiratory distress.

Differential Diagnosis

- Drug rash. Pruritic macular or maculopapular rash over trunk and extremities may progress to serum sickness. History of exposure to a drug usually started in the past 7 to 10 days for first exposure or 12 to 72 hours with re-exposure. Many drugs have more characteristic presentation or photoactivation. Eosinophilia is common.

- Drug Side Effect. All narcotics, especially morphine, may stimulate histamine release. This can cause itching, urticaria, and broncospasm in patients with reactive airway disease.

- Contact Dermatitis. Localized maculopapular, vesicular or pustular rash. May be under jewelry with nickel sensitivity, on face, eyes, or ears with cosmetic sensitivity, or linear with poison ivy, oak, or summac.

- Urticaria. Pruritic, erythematous, edematous wheals, "hives". History of exposure to known allergen is helpful. Careful drug, dietary, recent infection, exercise or exposure to cold, and habit history may be required. This can be seen from the histamine release by narcotics.

- Angioneurotic Edema. Tightness in throat, loss of voice, difficulty swallowing, edema of uvula, soft palate, or pharynx, and stridor.

- Bronchospasm. Wheezing, stridor, loss of voice, and prolonged expiratory phase of respiration with respiratory distress and cyanosis establishes airway involvement. Patient will often have a history of asthma or family history may be positive.

- Anaphylaxis. Hypotension or shock with or without other findings of allergic reaction with recent exposure to medication, allergen extract, insect sting, or food support this diagnosis. Patient may have peripheral dilatation and edema.

Treatment

- Drug Rash. Stop suspect medication. Administer hydroxyzine, diphenhydramine, or other H1 antihistamine in appropriate dosage to control itching. If severe or chronic consider cimetidine, oral steroids, and Dermatology consult.

- Drug Side Effect. Treatment with hydroxyzine 0.2 – 0.5 mg/kg/dose up to 25 mg every 8 hours or diphenhydramine 0.5 to 1.0 mg/kg/dose up to 50 mg every 6 hours will reduce or prevent symptoms of histamine release.

- Contact Dermatitis. Discontinue contact agent and apply 1% hydrocortisone cream q.i.d. if skin is intact. Burow’s solution may control itching and is used if weeping is present. If severe, obtain a Dermatology consult and consider starting oral steroids.

- Urticaria. Discontinue allergen. Epinephrine (1:1000) 0.01 ml/kg up to 0.3 cc SQ or IM will cause acute improvement. Hydroxyzine 0.2 - 0.5 mg/kg/dose up to 25 mg q 8 h or diphenhydramine 1 mg/kg/dose (up to 50 mg) q 6 h is given for itching. Cyproheptadine, cimetidine or systemic steroids.

- Angioneurotic Edema. Treat as for urticaria but always give epinephrine. An I.V. should be started and I.V. or I.M. antihistamines should be given. Tracheostomy could be required for severe, unresponsive episodes. If episodes are recurrent, consider C’ esterase inhibitor deficiency.

- Bronchospasm. Administer terbutaline sulfate (1 mg/ml) 0.01 mg/kg/dose SQ or IM given q 20 minutes X 2 or epinephrine (1.1000) 0:01 ml/kg/dose up to 0.5 cc SQ may repeat q 20-30 minutes X3, start nasal O₂ at 6 - 8L. Metaproterenol or terbutaline inhalers 1 to 2 puffs every 4 hours. Nebulized agents include iosetharine (1%) 0.15 - 0.5 ml in 1 ml of water or metaproterenol (5%) 0.1 - 0.3 diluted in 2 mls with water. and start aminophylline 6 - 9 mg/kg IV (LOADING DOSE GIVEN OVER 30 MINUTES).

- Anaphylaxis.- Administer epinephrine. If I.V. access available give (1:10,000) 2-4 cc I.V. and start an infusion of 0.5 to 5 µg/min by diluting 1 cc of 1:1000 epinephrine in 500 cc of D5W and infuse at 0.25 to 2.5 ml/min. If no I.V. access is available, give (1:1000) 0.2 - 0.4 cc IM immediately and repeat q 10 - 20 minutes if blood pressure <100 and pulse <160.

- Maintain airway and give O2 at 8 L/min- Start normal saline and run 1 L in over 5-10 minutes if hypotensive. Adjust further rate by response.

- If hypotension is resistant to previous treatment start dopamine 5-25 micrograms/kg/minute.

- After the patient is stable, give hydrocortisone 500 mg IV push and repeat q 6 hours to prevent relapse.

- All patients with anaphylaxis should be admitted for 24 hours observation because recurrences are not uncommon.

Nursing Considerations:

Educate patients and family about the avoidance of known allergens in foods and the environment

 Stress smoke avoidance, dust free environment, use of hypo allergenic bedding and discourage house pets

 Assess patients for idiosyncratic reactions

 Insure that allergies are clearly noted in patient’s medical records

 Assess allergy history, include latex allergy history and avoid use of gloves or latex products

 Assess history of medication side effects and provide education, patients may discontinue medications because of side effects assuming that they are allergic to medication

Patient Education and Prevention

Environmental control of exposure to known allergens is the most important methods of control. Careful history to define all allergies, particularly those related to medications. Patients with severe asthma or reactions to insect bites should carry emergency kits. Desensitization may be indicated for frequent or severe allergic attacks. Medical alert jewelry should list allergies and symptoms along with the hemoglobinopathy.

Education involves careful coaching about the avoidance of allergens in foods or the environment. Avoiding smoking, keeping the house dust free, and use of hypoallergenic bedding needs to be stressed. House pets are to be discouraged.

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References

Manual of Allergy and Immunology, Glenn J. Lawlor, Jr., Thomas J. Fischer, and Daniel C. Adelman editors, Lippincott Williams and Wilkins 1995

Pearlman DS and Comer CR. Allergic disorders. In Current Pediatric Diagnosis and Treatment. Hathaway WE, Groothuis JR, Hay WW, and Paisley eds. Appleton & Lange. Norwalk, Connecticut. 1991. pp. 973 - 996.

Beirman CW and Pearlman DS. Allergic Diseases from Infancy to Adulthood. 2nd ed. Saunders, 1988.

Lichtenstein LM and Fauci AS. Current Therapy in Allergy, Immunology, and Rheumatology. Dekker, 1988.

Bochner BS, Lichtenstein LM. Current Concepts:Anaphylaxis. New Engl. J. Med. 324:1785-1790, 1991