Etiology and pathogenesis
Urticaria is a vascular reaction of the skin characterized by mast cell degranulation In children they caused by several factors like allergic or hypersensitivity reactions food (fish, milk, tomatoes, citrus fruits, cocoa, strawberries), drugs (aspirin, pethidine, hydralazine, ibuprofen) insect bites (bee, wasp, mosquito).Also viral infections, mycotic infections, helminthic infections and skin contact with allergens can be a cause. Physical urticaria may be induced by cold, heat, pressure and exercise. In the majority of the cases, the cause remains unidentified.
Urticaria are well demarcated small (< 1 cm) to large (> 8cm) smooth, slightly elevated patches (wheals) which can itch severely. Individual lesions are self-limiting and resolve in several hours but may be recurrent over weeks. Chronic urticaria is defined as urticaria with episodes lasting longer than 6 weeks. They are erythematous or white with an erythematous rim. The erythema which may be prominent in a light skin is not visible on a dark skin. Lesions can be oval, annular or serpiginous. They can appear anywhere and at any interval on the body and as angioedema in the face. The lesions are prutitic. Some patients also show dermographism. Normally urticaria in children is an isolated event, a massive reaction may occur which can lead to an anaphylactic shock.
- Avoid or treat the cause if possible. A thorough history is essential.The treatment depends on the severity, the duration and the type of hives.
- Further investigations, unless aimed at a specific suspected cause, are usually negative and not helpful. Only in debilitating chronic urticaria the following may be considered: Blood count, liver function test, kidney function test, infection parameters, allergy test and tests for autoimmune diseases.
- The most common treatment is oral antihistamines which controls the itching. Wheals may still be visible.
- Piriton (chlorphenamine maleate) ( British National Formulary)
- Child under 1 year not recommended.
- Child 1-2 years: 1 mg twice daily.Oral solution (Syrup, chlorphenamine, 2mg/5mL) 2.5ml twice daily.
- Child 2-5 years: 1 mg 4 to 6 times daily, maximum 6 mg daily.Oral solution (Syrup, chlorphenamine, 2mg/5mL) 2.5ml 4 times daily.
- Child 6-12 years: 2 mg 4 to 6 times daily, maximum 12 mg daily.Tablets (chlorphenamine, 4 mg) ½ tablet 4 times daily.
- Above 12 years: 4 mg 4 to 6 times daily, maximum 24 mg daily.Tablets (chlorphenamine), 4 mg) 1 tablet 4 times daily.
- Phenergan (promethazine) ( British National Formulary)
- Child under 2 years not recommended.
- Child 2-5 years : 5-15 mg daily in 1-2 divided doses.Oral solution (Syrup, promethazine, 5mg/5mL) 5-15ml daily in 1-2 divided doses.
- Child 5-10 years: 10-25 mg daily in 1-2½ divided doses.Tablets (promethazine 10 mg) 1- 2½ tablet in 1-2 divided doses.
- Above 10 years: 25 mg at night, increased to 25 mg twice daily if necessary.Tablets (promethazine 25 mg) 1 tablet 2 times daily.
- Cetirizine (cetirizine) ( British National Formulary)
- Child under 2 years not recommended.
- Child 2-6 years: 5 mg daily or 2.5 mg twice daily.Oral solution (Syrup, cetirizine hydrochloride, 5mg/5mL) 5 mL daily or 2.5ml twice daily.
- Child over 6 years: 10 mg daily or 5 mg twice daily.Tablets (cetirizine hydrochloride 10mg) 1 tablet daily or ½ tablet twice daily.
- If the first antihistamine is not effective, it might be necessary to increase the dose, or use a different antihistamine. Sometimes a combination of antihistamines is effective.
- In case of dermographism a combination of H1 (like Piriton) and H2 (like cimetidine) antihistamines is advisable.
- Oral steroids (prednisolon) in moderate dose for a few days can be helpful in severe cases of acute hives. They are not recommended long term because of adverse effects. Topical steroids like betamethason cream might be used twice daily for a short period in the case of severe itching.
- Avoid the use of aspirin, codeine and nonsteroidal anti-inflammatory drugs like ibuprofen.
- ↑ Dogra S, Kumar B. Epidemiology of skin diseases in school children: a study from northern India. Pediatr Dermatol 2003; 20: 470-3.
- ↑ El-Khateeb EA, Imam AA, Sallam MA. Pattern of skin diseases in Cairo, Egypt. Int J Dermatol 2011; 50: 844-53.
- ↑ Schafer T, Ring J. Epidemiology of urticaria. Monogr Allergy 1993; 31: 49-60.
- ↑ Ponvert C. [Allergic and non-allergic hypersensitivity to non-opioid analgesics, antipyretics and nonsteroidal anti-inflammatory drugs in children: Epidemiology, clinical aspects, pathophysiology, diagnosis and prevention.]. Arch Pediatr 2012.
- ↑ 5.0 5.1 van Hees C, Kunkeler L, Amalia C et al. Cutaneous allergies in Tropical countries, Expert reviews of Dermatology ;. Volume 2, Number 5, october 2007.
- ↑ 6.0 6.1 Zuberbier T, Asero R, Bindslev-Jensen C et al. EAACI/GA(2)LEN/EDF/WAO guideline: definition, classification and diagnosis of urticaria. Allergy 2009; 64: 1417-26.
- ↑ Dibbern DA, Jr. Urticaria: selected highlights and recent advances. Med Clin North Am 2006; 90: 187-209.
- ↑ 8.0 8.1 Grattan CE, Humphreys F. Guidelines for evaluation and management of urticaria in adults and children. Br J Dermatol 2007; 157: 1116-23.
- ↑ Tarbox JA, Gutta RC, Radojicic C et al. Utility of routine laboratory testing in management of chronic urticaria/angioedema. Ann Allergy Asthma Immunol 2011; 107: 239-43.