Hives (urticaria)

Question 1

what it urticarcia

Answer 1

• hives
• can affect patients at any age, has lifetime prevalence around 20%
• can be acute (lasting 6 weeks) or chronic (more than 6 weeks)
• typically benign and self limiting but can be a symptom of life threatening anaphylaxis or rareyl indicate significant underlying disease

Question 2

Pathophysiology of hives

Answer 2

• histamine and toher mediators are released from mast cells and basophils
• if the release occurs in the dermis is causes hives, if occurs in deeper dermis and subcutaneous tissue results in agioedema
• IgE often mediates release of histamine but non-IgE mediators also exist

Question 3

what are the 3 main potential causes of hives

Answer 3

• IgE mediated: contact or food allergens, insect venom, medication

Non-IgE mediated: autoimmune idease, infections, lymphoma, vasculitis

Non-immunologically mediated: elevation of core body temp, light, physical stimuli, medication

Question 4

clinical presentation of hives

Answer 4

• red or skin coloured wheals that are raised and well-circumscribed, often with centeral pallow
• can be less than a cm to several
• can be round, oval ro wave
• can coalesce as they inlarge
• often intensely pruitic, some cases burn or sting
• symptoms can last from minutes -> months or yeats but generally last less than 24 hours

Question 5

red flag signs and symptoms

Answer 5

Angioedema is present

They are experiencing stridor, wheezing, or other indicators of respiratory distress

There are signs or symptoms of a systemic illness

The lesions are hyperpigmented, bruised, blistered, or ulcered, or

The lesions have persisted for more than 48 hours

Question 6

general management for hives

non pharm

Answer 6

• want ot identify and remove cause of skin reaction, prodive symptomatic relief until spontaneous resolution occurs
• mainstay of treatment is avoiding the trigger
• can wear loose fititng lcohtes, cool baths/ apply cool compress, gentle fragrance free soaps and detergents
• keep nails short to prevent fingernail traume with scratching

Question 7

common drugs that can worsen hives

Answer 7

Alcohol and medications like acetylsalicylic acid and NSAIDs should be avoided, as these may worsen symptoms.

Question 8

when to treat hives with pharm measures

Answer 8

ndicated when trigger avoidance is not possible

when no trigger can be identified

symptom relief is needed despite trigger avoidance.

Question 9

first line treatment for acute hives

Answer 9

H1-antihistamines have been shown to reduce wheal formation, pruritus, and disruption of sleep and other daily activities

• use second gen (cetirizine and desloratadine) as first line because longer acting and relatively non sedating
• can consider first gen at bedtime in younger healthy patients to help with seep

*avoid frist gen in older patients due to anticholinergic side effects

Question 10

increasing dose of second generation antihistamines

Answer 10

in some cases they are titrated to two to four times their normal dose to control symptoms

• increases risk of adverse effects, not recommneded in context of self treatment

Question 11

topical antihistamines for treatment of hives

Answer 11

not recommended due to risk of contact dermatitis

Question 12

what to do when hives are not sufficiently controlled with second generation anti histamines

Answer 12

• add ranitidine (H2 antihistamine, ntoe tohers are H1)
• generally not required due to limited data to support

Question 13

when to add corticosteroids for hives

Answer 13

severe cases like angioedema or if symptoms persist mroe than a few days

• short course of oral corticosteroid (prednisone or prednisolone)
• > patient referral required (RPh cannot prescribe for this)

Question 14

when to suggest carrying around epipen

Answer 14

cases where systemic symptoms are suggested and identified a trigger assocaited with more severe reaction (insect stings, certain foods)

• carry epinephrine autoinjector to treat anaphylaxis if it were to occur

Question 15

first line treatment for chornic hives

Answer 15

second generation H₁-antihistamines at standard dose

• dose these agents daily rather than prn

*. Some evidence suggests that cetirizine may be modestly more effective than other agents in treating chronic hives.

Question 16

what is the step up if 2nd gen antihistmaines are not sufficient to control chronic hives

Answer 16

• if fail to provide sufficient control of sympoms within 2-4 weeks (or sooner if symptoms are intolerable) dose can be titrated up to 4x usual dose
• increases risk of adverse effects like sedation, not recommneded in contect of self care

Question 17

what is the step up if increased dose 2nd gen antihistmaines are not sufficient to control chronic hives?

What after that?

Answer 17

• add on omalizumab
• if thats still inadequate in 6 monnths, add cyclosporine to second gen H₁ antihistamine therapy instead

*Therapy with omalizumab or cyclosporine should be under the supervision of a specialist.

Question 18

alternative treatment options if none of mainstay step ups for chonic hives work

Answer 18

• consider H2-antihistamine, but these receptos are not involved in itch
• leukotriene receptor antagonist (e.g., montelukast) could be prescribed and may be particularly useful in patients with an NSAID intolerance or cold urticaria.

*RPh cant prescribe that

• finally doxepin (tricyclic antidepreaant) could be prescribed

*others are Dapsone, phototherapy or IV immunoglobulins -> but no studies directly comparing these interventions

Question 19

corticosteroids in treatment of chronic hives

Answer 19

• potent topical corticosteroids can use when symptoms are severe (flare up)
• may be beneficial for localized delayed pressure urticaria

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Question 20

monitoring and follow up for hives

Answer 20

• patients or caregivers monitor daily
• RPh in 7 days
• if no imporvement or worsening, refer
• in case of chornic hives, spontaneous remission can occur at any time, evaluate every 3-6 months