Angioedema

Angioedema is swelling of the deep layers of the dermis and subcutaneous tissues. It can be caused by drugs, poison (especially of animal origin), food or extracted allergens. The main symptom is diffuse, painful swelling, sometimes localized. Diagnosis is based on a general examination. Treatment is aimed at eliminating or stopping the allergen and prescribing H2 blockers.

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Causes of Angioedema

Acute angioedema is practically an anaphylactic reaction of the subcutaneous tissues. It is sometimes accompanied by urticarial rash (localized blisters and erythema on the skin); in both cases, the causes are similar (e.g., drugs, poisons, food and extracted allergens). Angioedema is pathogenetically related to urticaria, which manifests itself at the level of the epidermal-dermal junction.

Chronic (> 6 weeks) angioedema is rarely IgE-mediated, more often an unexplained disorder. The cause is usually unknown (idiopathic edema), but sometimes the cause is chronic use of unconcerned drugs or other synthetic products (penicillin in milk, over-the-counter drugs, preservatives, other food additives). In some cases, angioedema is congenital.

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Symptoms of angioedema

Mild pruritus may or may not be present in angioedema. The condition is characterized by localized, diffuse, and painful swelling of soft tissues that may be asymmetrical; the areas most susceptible to swelling are the eyelids, lips, face, tongue, back of the hands, feet, and genitals. Upper airway edema may cause respiratory distress, and stridor is sometimes mistaken for asthma. Complete airway obstruction may occur.

Diagnosis of angioedema

The cause is often obvious, and diagnostic tests are rarely performed because the reactions are self-limited and do not recur. No tests are particularly necessary for diagnosis. Erythropoietic protoporphyria may masquerade as allergic forms of angioedema and is diagnosed by measuring the amount of porphyrins in the blood and faeces.

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Treatment of angioedema

In acute angioedema, treatment consists of eliminating or avoiding the allergen and administering symptomatic drugs (e.g., H2 blockers). In the most severe cases, prednisolone 30-40 mg once daily is prescribed. Local glucocorticoid therapy is useless. Unless the cause is obvious, all non-essential drugs should be discontinued. In case of swelling of the pharynx or larynx, ephedrine 0.3 ml in a 1:1000 solution is prescribed subcutaneously. Treatment may be supplemented by intravenous antihistamines (diphenhydamine 50-100 mg). Long-term treatment may include H1 and H2 blockers and sometimes glucocorticoids.

Oral H1 blockers

Preparation	Dosage for adults	Dosage for children	Available dosage forms
Azatadine maleate	1-2 mg 2 times a day	< 12 years: not recommended. > 12 years: at adult dosage	Tablets 1 mg
Brompheniramine maleate	4 mg every 4-6 hours or 8 mg every 8-12 hours	< 6 years: 0.125 mg/kg every 6 hours (maximum dose 6-8 mg per day). 6-12 years: 2-4 mg every 6-8 hours (maximum dose 12-16 mg per day). > 12 years: at adult dosage	Tablets 4, 8, 12 mg. Elixir 2 mg/5 ml. Tablets 8.12 mg (extended release)
Chlorpheniramine maleate	2-4 mg every 4-6 hours	< 6 years: not recommended. 6-11 years: 2 mg every 4-6 hours (maximum dose 12-16 mg/day). > 12 years: at adult dosage	Chewable tablets 2 mg. Tablets 4, 8, 12 mg. Syrup 2 mg/5 ml. Tablets or capsules 8, 12 mg
Clemastine fumarate	From 1.34 mg 2 times a day to 2.68 mg 3 times a day	6-12 years: 0.5 mg every 12 hours (maximum dose 3 mg/day) 3	Tablets 1.34; 2.68 mg. Syrup 0.67 mg/5 ml
Cyproheptadine HCI	4 mg 3 or 4 times daily [maximum dose 0.5 mg/(kg/day)]	2-6 years: 2 mg 2 or 3 times a day (maximum 12 mg/day). 7-14 years: 4 mg 2 or 3 times a day (maximum 16 mg/day)	Tablets 4 mg. Syrup 2 mg/5 ml
Dexchlorpheniramine maleate	2 mg every 4-6 hours	2-5 years: 0.5 mg every 4-6 hours (maximum dose 3 mg/day). 6-11 years: 1 mg every 4-6 hours (maximum dose 6 mg/day)	Tablets 2 mg. Syrup 2 mg/5 ml. Tablets 4.6 mg. (extended release)
Diphenhydramine	25-50 mg every 4-6 hours	1.25 mg/kg every 6 hours (maximum dose 300 mg/day)	Capsules or tablets 25, 50 mg. Syrup 12.5 mg/ml. Elixir 12.5/5 ml
Diphenylpyralin	5 mg every 12 hours	No data available	Capsules 5 mg (extended release)
Hydroxyzine HCI	25-50 mg 3 or 4 times a day	0.7 mg/kg 3 times a day	Capsules 25, 50,100 mg. Tablets 10,25,50 and 100 mg. Syrup 10 mg/5 ml. Oral suspension 25 mg/5 ml.
Methdilazine HCI	8 mg every	> 3 years: 4 mg every	Tablets 8 mg. Chewable tablets 4 mg. Syrup 4 mg/5 ml
Promethazine HCI	12.5-25 mg 2 times a day	< 2 years: contraindicated. 2 years: 6.25-12.5 mg 2 or 3 times a day	Tablets 12.5; 25; 50 mg. Syrup 6.25 and 25 mg/5 ml
Trimeprazine tartrate	2.5 mg 4 times	6 months - 3 years: 1.25 mg at night or 3 times a day. > 3 years: 2.5 mg at night or 3 times a day.	Tablets 2.5 mg. Syrup 2.5 mg/5 ml. Capsules 5 mg (extended release)
Tripelennamine citrate	25-50 mg every 4-6 hours	1.9 mg/kg 4 times daily (maximum 450 mg/day)	Elixir 37.5 mg/5 ml (1 ml citrate = 5 mg HCI salt)
Tripelennamine HCI	25-50 mg every 4-6 hours	1.25 mg/kg 4 times daily (maximum 300 mg/day)	Tablets 25; 50 mg. Tablets 100 mg (extended release)
Triprolidine HCI	2.5 mg every 4-6 hours (maximum 10 mg/day)	4 months - 2 years: 0.313 mg every 4-6 hours (maximum 1.25 mg/day). 2-4 years: 0.625 mg every 4-6 hours (maximum 2.5 mg/day). 4-6 years: 0.938 mg every 4-6 hours (maximum 3.744 mg/day). 6-12 years: 1.25 mg every 4-6 hours (maximum 5 mg/day)	Tablets 2.5 mg. Syrup 1.25 mg/5 ml

No sedative effect

Preparation	Dosage for adults	Dosage for children	Available dosage forms
Acrivastine	8 mg 2 or 3 times	< 12 years: not recommended. 12 years: adult dosage	Capsules 8 mg
Cetirizine	5-10 mg 1 time	> 12 years: at adult dosage	Tablets 5.10 mg
Desloratadine	5 mg once a day	> 12 years: at adult dosage	Tablets 5 mg
Ebastine	10-20 mg 1 time per day	6-12 years: 5 mg. 12-17 years: 5-20 mg once a day.	Tablets 10 mg
Fexofenadine	60 mg 2 times a day or 180 mg 1 time per day	6-11 years: 30 mg 2 times a day. 12 years: adult dosage	Tablets 60,180 mg
Levocetirizine	5 mg once a day	No data available	Tablets 5 mg
Loratadine	10 mg 1 time	2-5 years: 5 mg once daily. 6 years: in adult dosage	Tablets 10 mg. Syrup 1 mg/1 ml
Mizolastine	10 mg 1 time	No data available	Tablets 10 mg

All antihistamines with sedative effect have anticholinergic properties. They are generally not used in the elderly and in patients with glaucoma, benign prostatic hyperplasia, delirium, dementia and orthostatic hypotension. When taking these drugs, dry mouth, decreased visual acuity, urinary retention, constipation, orthostatic hypotension are observed.