Evaluation of urticaria

Urticaria, also known as welts, hives, or wheals, is characterized by the appearance of intensely pruritic erythematous plaques.[1]Bernstein JA, Lang DM, Khan DA, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol. 2014 May;133(5):1270-7. http://www.ncbi.nlm.nih.gov/pubmed/24766875?tool=bestpractice.com It appears clinically as pruritic, pale, blanching swellings of the superficial dermis that last for up to 24 hours. Lesions may be small, large, giant, oval, or annular.[Figure caption and citation for the preceding image starts]: Acute urticaria: typical whealsFrom the collection of Adam Reich, MD, PhD [Citation ends].[Figure caption and citation for the preceding image starts]: Typical lesions seen in acute or chronic urticariaFrom the collection of Stephen Dreskin, MD, PhD [Citation ends].[Figure caption and citation for the preceding image starts]: Urticaria: whealsFrom the collection of Adam Reich, MD, PhD [Citation ends].

Urticaria affects 10% to 25% of the population and can occur in any age group.[2]Guldbakke KK, Khachemoune A. Etiology, classification, and treatment of urticaria. Cutis. 2007 Jan;79(1):41-9. http://www.ncbi.nlm.nih.gov/pubmed/17330621?tool=bestpractice.com ​​ It is a mast-cell-driven disease. The triggering mechanisms for mast-cell activation in urticaria are not well defined but seem to be multiple and diverse.[3]European Dermatology Forum. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria. Sep 2021 [internet publication]. https://www.guidelines.edf.one//uploads/attachments/cl263w4y200oilajn3li6nqa1-urticaria-2021-gl.pdf

Urticaria is classified according to duration of symptoms:

• Acute urticaria: the occurrence of spontaneous wheals, angioedema, or both for <6 weeks[1]Bernstein JA, Lang DM, Khan DA, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol. 2014 May;133(5):1270-7. http://www.ncbi.nlm.nih.gov/pubmed/24766875?tool=bestpractice.com [2]Guldbakke KK, Khachemoune A. Etiology, classification, and treatment of urticaria. Cutis. 2007 Jan;79(1):41-9. http://www.ncbi.nlm.nih.gov/pubmed/17330621?tool=bestpractice.com [3]European Dermatology Forum. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria. Sep 2021 [internet publication]. https://www.guidelines.edf.one//uploads/attachments/cl263w4y200oilajn3li6nqa1-urticaria-2021-gl.pdf ​​​​​

• Chronic urticaria: urticaria that has been continuously or intermittently present for ≥6 weeks.​​[1]Bernstein JA, Lang DM, Khan DA, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol. 2014 May;133(5):1270-7. http://www.ncbi.nlm.nih.gov/pubmed/24766875?tool=bestpractice.com [3]European Dermatology Forum. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria. Sep 2021 [internet publication]. https://www.guidelines.edf.one//uploads/attachments/cl263w4y200oilajn3li6nqa1-urticaria-2021-gl.pdf [4]Sabroe RA, Lawlor F, Grattan CEH, et al. British Association of Dermatologists guidelines for the management of people with chronic urticaria 2021. Br J Dermatol. 2022 Mar;186(3):398-413. https://academic.oup.com/bjd/article/186/3/398/6705777 http://www.ncbi.nlm.nih.gov/pubmed/34773650?tool=bestpractice.com

Chronic urticaria is classified into 2 subtypes:[3]European Dermatology Forum. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria. Sep 2021 [internet publication]. https://www.guidelines.edf.one//uploads/attachments/cl263w4y200oilajn3li6nqa1-urticaria-2021-gl.pdf ​​

• Chronic spontaneous urticaria: spontaneous appearance of wheals, angioedema, or both ≥6 weeks due to known or unknown causes.

• Inducible urticaria, for example delayed pressure urticaria, heat urticaria, solar urticaria, symptomatic dermatographism, vibratory angioedema, aquagenic urticaria, cholinergic urticaria, and contact urticaria.

Urticaria complicated by angioedema

Some people have urticaria that is complicated by angioedema, a swelling of the deeper dermis and tissues (e.g., mucosal surfaces), with laryngeal edema potentially causing respiratory distress and death.[3]European Dermatology Forum. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria. Sep 2021 [internet publication]. https://www.guidelines.edf.one//uploads/attachments/cl263w4y200oilajn3li6nqa1-urticaria-2021-gl.pdf ​ Angioedema is commonly associated with urticaria and may occur at any age.[5]Katelaris CH, Peake JE. MJA practice essentials 5. Allergy and the skin: eczema and chronic urticaria. Med J Aust. 2006 Nov 6;185(9):517-22. http://www.mja.com.au/public/issues/185_09_061106/kat10399_fm.html http://www.ncbi.nlm.nih.gov/pubmed/17137459?tool=bestpractice.com It may not necessarily be seen at the first urticarial episode, but risk of angioedema increases with greater exposure to the allergenic substance.[6]Grattan CEH, Black AK. Urticaria and angioedema. In: Bolognia JL, Jorizzo JL, Rapini RP ed. Dermatology (volume one). London, UK: Mosby; 2003;287-302.

Clinical presentation of angioedema may include nonpitting edema of the subcutaneous tissues involving lips, face, neck and extremities and/or submucosal tissues affecting the oral cavity, larynx and gastrointestinal system.[7]Depetri F, Tedeschi A, Cugno M. Angioedema and emergency medicine: From pathophysiology to diagnosis and treatment. Eur J Intern Med. 2019 Jan;59:8-13. http://www.ncbi.nlm.nih.gov/pubmed/30220453?tool=bestpractice.com ​ Associated symptoms may also be present. These are dependent on the underlying etiology. Examples include flushing, bronchospasm, abdominal pain, diarrhea and vomiting.[7]Depetri F, Tedeschi A, Cugno M. Angioedema and emergency medicine: From pathophysiology to diagnosis and treatment. Eur J Intern Med. 2019 Jan;59:8-13. http://www.ncbi.nlm.nih.gov/pubmed/30220453?tool=bestpractice.com ​ Angioedema without urticaria should prompt further evaluation.[1]Bernstein JA, Lang DM, Khan DA, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol. 2014 May;133(5):1270-7. http://www.ncbi.nlm.nih.gov/pubmed/24766875?tool=bestpractice.com [Figure caption and citation for the preceding image starts]: Angio-oedema of the lips in a patient who also has urticariaFrom the collection of Stephen Dreskin, MD, PhD [Citation ends].