Approach to Managing Anaphylaxis to Rare Allergens

Introduction:

Anaphylaxis can be described as a potentially life-threatening systemic hypersensitivity reaction associated with airway and/or circulation problems. Anaphylaxis presents with varied clinical symptoms, and unfortunately, at times, milder signs do progress to fatal complications. Anaphylaxis is a rapidly developing life-threatening airway and/or circulatory complication and should be managed quickly. Recognizing the diverse clinical features and taking a detailed history of previous allergen exposure can aid in appropriate, timely diagnosis and effective clinical management.

What Is Anaphylaxis?

Anaphylaxis is a rare but life-threatening medical emergency that is usually triggered by exposure to an allergen (previously encountered). It is an IgE (Immunoglobulin E)-mediated hypersensitivity reaction in response to the body’s exposure to food or drug allergens or to the envenomation of insect bites. When the body is allergic to certain foods or drugs, the immune system is overstimulated, and releases chemicals like histamine, which triggers an inflammatory reaction, and signs like itchy, watery eyes and a runny nose can be seen. This is a type of local reaction and is less severe. But in some cases, inflammation occurs in a generalized form where almost the whole of the body is involved, resulting in an anaphylactic reaction. Symptoms include swelling, wheezing, shortness of breath, and difficulty in swallowing.

What Changes Occur When the Body Encounters an Anaphylactic Reaction?

When the body gets exposed to an allergen (antigen), it results in interaction between the antigen and IgE antibodies on basophils and mast cells, triggering the release of pro-inflammatory chemical substances such as histamine, leukotrienes, and other mediators leading to smooth muscle contraction. This causes bronchoconstriction, vomiting, and diarrhea. Vasodilation with plasma leakage results in urticaria (itchy rashes on the skin) or angioedema (painless swelling beneath the skin).

What Are the Rare Allergens Causing Anaphylactic Reactions?

Exercise With or Without Food:

• Anaphylactic reactions can be encountered suddenly during any physical activity, such as running on a treadmill in a gym or in brisk walking, causing severe tiredness, fatigue, warmth, flushing, wheezing, itching, and facial swelling. Sometimes, symptoms can appear due to pre-workout food intake.

Semen Allergy in Susceptible Women:

• Sperm allergy is also referred to as semen allergy. This is a very rare cause of anaphylaxis occurring in women during or after intercourse, leading to life-threatening complications. Women with allergic asthma and atopic dermatitis are more prone to anaphylaxis.

Menstrual Cycle:

• Anaphylaxis can occur before or during the menstrual cycle. Also called catamenial or cyclic anaphylaxis (a widespread allergic reaction). This often goes unnoticed. Sometimes, medications or food consumed around the time of menses can lead to anaphylaxis.

Latex Allergy:

• Healthcare workers, hairdressers, and housekeepers are more susceptible to latex allergy.

Meat Allergy:

• Pork, beef, lamb, veal, venison, and rabbit meat can cause anaphylactic reactions postprandially.

Insect Stings:

• Stings of bees, hornets, and wasps, including yellow jackets and fire ants, can sometimes trigger life-threatening anaphylactic reactions.

Idiopathic: (Unknown Cause):

• Sometimes, anaphylaxis occurs due to an unknown cause, and the etiological factor cannot be tracked. A careful history and physical examination with appropriate management can prevent further complications.

What Are the Clinical Features of Anaphylaxis?

Anaphylaxis is a systemic allergic reaction involving various organs of the body that includes,

Prodromal Symptoms:

1. Itching or burning sensation in the palms, soles, or genital region.

2. Metallic taste.

3. Fearfulness.

4. Headache.

5. Disorientation.

Skin and Mucous Membrane:

1. Pruritus (itchy skin).

2. Erythema (flush).

3. Urticaria (itchy rashes on the skin).

4. Angioedema (Quincke’s edema) can occur in the area that is not triggered by the allergen (systemic spread).

Upper Respiratory Tract:

1. Muffled voice.

2. Dysphagia with salivation (difficulty in eating accompanied by salivation).

3. Inspiratory stridor (an abnormal high-pitched sound heard during breathing, especially while taking the air in).

4. Wheezing.

5. Prolonged expiration.

6. Increased respiratory rate.

7. Laryngeal edema (swelling involving the larynx or windpipe region)

8. Airway obstruction.

Gastrointestinal Tract:

1. Cramps.

2. Abdominal pain.

3. Nausea and vomiting.

4. Diarrhea.

5. Involuntary defecation and micturition (uncontrolled bowel movements and urination).

Cardiovascular System:

1. Hypovolemia.

2. Arterial hypotension.

3. Tachycardia (increased heart rate).

4. Arrhythmia (irregular heartbeat).

5. Bradycardia (decreased heart rate).

6. Myocardial infarction (heart attack).

Nervous System:

1. Restlessness.

2. Withdrawal behavior.

3. Headache.

4. Seizures.

5. Altered mental status.

6. Anxiety and aggression in children.

How Is Anaphylactic Reaction Diagnosed?

• Sudden occurrence of acute urticaria, angioedema, flush, and swelling of mucous membranes accompanied with respiratory symptoms like dyspnea, wheezing, cough, and stridor with or without a rapid decrease in the blood pressure gives a clue.

• Clinical manifestations involving two or more organ symptoms like skin (acute urticaria, angioedema) and gastrointestinal tract symptoms (abdominal cramps, vomiting), possibly after getting in contact with an allergic or anaphylactic trigger substance.

• Occurrence of hypotension subsequently after coming in contact with an allergen or the second anaphylactic trigger.

• A detailed history is taken, and a thorough physical examination is carried out by taking the following measures.

1. Vital signs are checked.

2. Blood pressure and pulse rate are measured.

3. Evaluation of breathing is done and assessed for dyspnea on speaking, inspiratory or expiratory stridor, and wheezing.

4. Inspection of visible skin and mucous membranes is done to rule out any abnormal signs.

5. A previous history of nausea, headache, sternal pressure, vision disturbances, and pruritus is noted.

6. A history of known allergies is noted.

How Is Anaphylactic Reaction Treated?

• Adrenaline is the drug of choice administered to counteract the pathomechanism caused by anaphylaxis. Adrenaline acts by activating α- and β-adrenergic receptors, causing vasoconstriction, reduced vascular permeability, bronchodilation, and reduced edema.

• Adrenaline is administered intravenously and is the most potent of all anaphylactic drugs and shows the fastest onset of action of all anaphylaxis drugs.

• Dopamine of 2 to 15 μg/kg/minute is administered to counteract the pathomechanisms of the cardiovascular system by acting on α and β adrenoreceptors and has a shorter half-life.

• An adequate supply of 100 percent oxygen is done in case of cardiovascular or pulmonary reactions and is supplied through a reservoir bag. Administration of high flow 100 percent oxygen is recommended. A laryngeal mask or a laryngeal tube can be helpful.

• Glucocorticosteroids are effective in the treatment of asthma triggered by anaphylactic reactions.

Conclusion:

In most cases, anaphylaxis goes unnoticed. This is a systemic condition involving one or more organ systems presenting varied clinical features, and sometimes, the milder ones progress to fatal complications. Timely diagnosis is the key to successful management of the case. Managing anaphylaxis is quite challenging and requires an interpersonal approach. Health professionals require continuous training and education to deal with such cases prudently, thereby providing better treatment outcomes for such life-threatening medical emergencies.