Abstract: 

This is a review of Allergic emergencies encountered; in the practice of surgical dermatology. Anaphylaxis, 
Vasovagal syncope and lidocaine allergy. Recommendations for prevention and management are provided.

Anaphylaxis: 

Anaphylaxis is a generalized multiple organ immunologic reaction. This reaction may begin with the prodrome of cutaneous features including: diffuse erythema, pruritus or urticaria followed by inspiratory stridor, laryngoedema, bronchospasm, hypotension and cardiac arrhythmias. (1) Peak severity can occur within 5-30 minutes with potentially fatal ] consequences. (2) Anaphylaxis is believed to account for at least 500 deaths annually in the United States (3) The causes of the anaphylactic reactions in the dermatology office include: penicillin and cephalosporin injection, local injection of an ester anesthetic or lidocaine. (4) Few cases reported developed anaphylaxis from topical application of bacitracin or neomycin. (5) 

The key to anaphylaxis management is prompt recognition of the symptoms and signs. The patient should be placed supine on the examining table in the Trendelenburg position. The tight clothing loosened and administration of low-flow oxygen (l- 2Urnin.) by face mask is initiated. Minimize antigen exposure including wiping off the bacitracin or applying a tourniquet proximal to the injection site and activate the Emergency Medical 
Services(EMS). (6) 

Epinephrine is the crucial medication for the initial treatment of anaphylaxis, as it: 

0.3 -0.5 ml of epinephrine 1:1000 is administered subcutaneously, repeat dosage every 5-10 minutes if needed. The pediatric dose is 0.01 mI/kg. up to 0.5 ml maximum. (7) The physician should be prepared to initiate cardiopulmonary resuscitation (CPR) if respiratory failure and shock ensue. (6) Even if the patient regains consciousness and normal vital signs before EMS arrival, hospitalization for a 24-hour observation is advised. (7) 

Vasovagal Syncope 

Vasovagal syncope is the common cause of acute brief unconsciousness. It is more prevalent than anaphylaxis. The precipitating factors are: emotional stress, acute pain or fear although frequently no cause is identified. (8) A characteristic prodrome may include anxiety, nausea, tachypnea, tachycardia, confusion and collapse. The skin becomes pale and cool, blood pressure may initially decrease but is restored with recumbency. Conversely, anaphylaxis is characterized by warmth, erythematous, and recumbent hypotension. (7) 

TheTable contrasts the signs and symptoms of vasovagal syncope and anaphylaxis.

To minimize opportunities for vasovagal events advise the following: 

• The procedures as injections and biopsies should be performed with the patient in a supine position. In this position, these events rarely occur. 
  

• Complete explanation of the procedure to the patient may relieve the anxiety. 
  

• Vasovagal events may occur more frequently when the patient misses a meal before the procedure. 
  

• In a patient With a known history of vasovagal syncope, a towel should be draped over the eyes to avoid sight of blood and the surgical tray. 
  

• Conversation with the patient during the procedure is similarly beneficial. 
  

• After the procedure, the patient should slowly sit up and be watched for a few minutes. (7)
  

Should a vasovagal reaction develop, the patient is promptly restored to a recumbent position. A cool water wash cloth placed on the forehead with a low power fan directed toward the face is helpful. Briefly, early recognition, restoration of recumbency, and reassurance constitute the management approach to vasovagal syncope. (8) . 

Lidocaine allergy: 

Allergic reactions to pure lidocaine are extremely rare. It belongs to the amide family of anesthetics or Preservatives. Unlike the ester family which includes procaine, tetracaine, and benzocaine and more commonly elicit an allergic reaction because they are p-aminobenzoic acid (pABA) derivatives. (9) 

Excitation, perioral numbness, nausea, seizures or coma are common symptoms and signs of lidocaine allergy. (10) 

The management of lidocaine allergy is as already described for anaphylaxis. (7) 

Some have advocated an intradermal test dose (0.01 ml) of lidocaine with a 30-minute observation. In the absence of erythema the physician can proceed with pure lidocaine. (11) 

In summary, dermatologists may encounter many potential emergencies and medical issues in day-to-day practice. Each dermatology office should develop an emergency plan tailored to its Individual needs. The plan and practice guidelines should help allay the fear of an office emergency. 

References: 

1) Soto-Aguilar MC, deShazo RD, Waring NP. Anaphylaxis why it happens and what to do about it. Postgrad Med 1987;82: 154-70. 

2) Bochner BS, Lichtenstein LM. Anaphylaxis. N Engl J Med 1991; 324: 1785-90.
 
3) Kemp SF, Lockey RF, Wolf BL,et al. Anaphylaxis: a review of 266 cases. Arch Intern Med 1995; 155: 1749-54. 

4) Grekin RC, Aulletta MJ. Local anesthesia in dermatologic surgery. J AmAcad Dermato11988; 19: 599-4. 

5) Roupe G, Strennegard O. Anaphylaxis shock elicited by i topicaladministra'ion of bacitracin. Arch Dermato11969; 100: 4.50-2 

6) Luke WC, Thomas H. Anaphylaxis: Pathophysiology, clinical presentations and treatment. J Emerg Med 1983; 1: 83-95. 

7) Gordon BR. Prevention and management of office allergy emergencies. Otolaryngol Clin NorthAm 1992;25(1):119- 34. 

8) Martin JB, Ruskin J. Faintness, syncope and seizures. In: Harrisons Principles of internal medicine. 12th ed. New York: MacGraw-Hill, 1991; 134-40. 

9) Swanson JG. Assessment of allergy to local anesthetic. Ann Emerg Med 1983; 12: 316-8. 

10) Incaudo G, Schatz M, Patterson R, et al. Administration of local anesthetics to patients with a history of prior adverse reaction. J Allergy Clin Immunol1978; 61: 339-45. 

11) Aldrete JA, Johnson DA. Evaluation of intracutaneous 
testing for investigation of allergy to local anesthetic agents. Anesth analg 1970; 49: 173-81.