Urticaria is a common vascular reaction pattern in which the primary lesion is characteristically a wheal, itchy transient swelling which may be rose coloured or porcelain-like. The lesion occurs quickly and disappears within some hours without leaving any trace. Urticaria is associated with itching and there are many varieties of urticaria. The causes of urticaria are many: food, food additives, drugs, aspirin, infections (bacterial, virus), infestations (parasites), emotional stress, physical factors (cold, heat, light (UV), menthol - (found in cigarettes, candy and mints, cough drops, aerosol sprays and topical medications); inhalants, alcohol, collagen vascular diseases and neoplasms.
Diagnosis is established by:
1) observation of monomorphic wheals,
2) short time course
3) presence of pruritus and
4) healing of the lesion without leaving any trace.
Treatment:
See the table below
Table 2. Drugs Useful for Urticaria
H1-Receptor Antagonist |
Formulation |
Recommended therapy |
First Generation Antihistamines |
Chlorpheniramine |
Tablet, 4mg,8mg,12mg Syrup, 2.5mg/5ml. |
Adult: 8-12mg once daily or twice daily.
Child: 0.5mg/kg/24 hrs. |
Promethazine Hydrochloride |
Tablet, 10 mg, 25mg,
Elixir, 5mg/5ml.
Suppository,25 mg and 50mg
Injection,25 mg/ml in 1 ml and 2 m ampoules |
Adult: 10 mg p.o T.I.D p.o
Child: 2-5 years,5-15 mg/ day 5-10 years,10-25 mg/ day. |
Second Generation Antihistamines |
Loratadine |
Tablet, 10mg
Syrup, 5mg/5ml |
Adult: 10mg p.o. once daily
Child: 2-12 years-5mg p.o. daily >12 years & >30 kg 10mg p.o. daily |
Cetirizine hydrochloride |
Tablet, 5 mg and 10mg
Oral solution,1 mg/ml |
Adult: 5-10mg p.o. once daily
Child,2-6 years,5 mg /day
Or 2.5 mg b.i.d. |
Note:
Treatment should continue until the urticaria disappears and for a few days thereafter.
S/E: For first generation antihistamines: drowsiness and dry mouth
For second generation antihistamines: weight gain, rarely sedation and arrhythmia
