Urticaria

From Anvita Health Wiki

Contents 1 Introduction 2 Etiology 3 Epidemiology 4 Pathology 5 Clinical-manifestations 6 Laboratory 7 Radiology 8 Complications 9 Differential-diagnosis 10 Management 11 More General Terms 12 Additional Terms 13 References

Introduction

• Wheal ( swelling) & flare (redness) response to histamine release.

Etiology

• food allergy

• common cause of acute urticaria
• almost never causes chronic urticaria

• pharmacologic agents (common, perhaps most common cause)

• aspirin
• barbiturates
• captopril
• enalapril
• penicillins
• sulfonamides

• insect bite or sting
• airborne allergens
• contact allergens

• animal dander
• latex

• infections:

• bacterial ( H pylori)
• viral ( hepatitis B)
• fungal
• helminth

• intravenous radioactive iodine contrast agent
• transfusion reactions
• physical factors

• demographism (writing on the skin)
• vibratory urticaria, vibratory angioedema
• solar urticaria
• localized heat urticaria
• cold-induced urticaria - generally noted within minutes
• aquatic urticaria
• pressure urticaria

• immediate 5-10 minutes
• delayed 4-6 hours: may be associated with systemic symptoms (i.e. fever, systemic inflammation)

• cholinergic urticaria

• following hot shower or exercising in humid environment
• typically around neck, wheals small

• autoimmune disease

• cryoglobulinemia
• lupus erythematosus
• rheumatoid arthritis
• Sjogren's syndrome
• serum sickness
• premenstrual urticaria ( antibodies to IgE & progesterone implicated)
• Hashimoto's thyroiditis ( hypothyroidism)
• Grave's disease ( hyperthyroidism)
• Diabetes mellitus type 1
• may occur up to 10 years after onset of urticaria
• autoimmune diseases are 17 times more common in patients with idiopathic urticaria than in general population [8]

• malignancies

• acquired complement C1 & C1 inhibitor depletion
• Hodgkin's disease
• non-Hodgkin's lymphoma

• urticaria pigmentosum ( systemic mastocytosis)
• urticarial vasculitis
• hereditary disorders

• hereditary angioedema
• familial cold urticaria
• C3b inactivator deficiency
• amyloidosis with deafness & urticaria

• chronic idiopathic urticaria

• may be autoimmune disorder
• may be due to IgG directed against alpha chain of IgE receptor on mast cells
• hepatitis C [4]

• psychogenic factors & hyperthyroidism can exacerbate urticaria, but cannot be sole cause
• idiopathic (common)

Epidemiology

• occurs in 25% of population at some time
• chronic urticaria

• more common in adults
• female:male ratio is 2:1

Pathology

• release of histamine & other mediators from mast cells possibly related to IgE-mediated release

• 1/2 of patients with chronic idiopathic urticaria have IgE autoantibodies or antibodies against high-affinity IgE receptors on mast cells & basophils [8]

• dilation of blood vessels with extravasation of fluid into the interstitium
• mixed infiltrate of leukocytes surrounding dilated vessels
• urticaria involves the epidermis & upper regions of the dermis in contrast to angioedema which involves deeper layers of the dermis & subcutaneous tissue

Clinical-manifestations

• wheal ( swelling) & flare (redness)
• elevated, well circumscribed, erythematous, edematous, pruritic lesions

• papules or plaques
• edema is non- pitting

• episodes generally resolve spontaneously within 24-48 hours, most last 2-18 hours
• lesions generally resolve without scarring or discoloration
• chronic idiopathic urticaria

• recurrent episodes of urticaria lasting > 6 weeks
• episodes of angioedema generally occur, either alone or concurrently
• 40% still have urticaria after 10 years

Laboratory

• skin biopsy

• lesions lasting > 24-48 hours
• lesions leaving discoloration
• increased ESR or CRP

• urticaria of more than 6 weeks duration

• complete blood count ( CBC) with differential

• eosinophilia suggests parasitic infection

• strogyloidiasis, filariasis, trichinosis ( periorbital edema)

• increased erythrocyte sedimentation rate (ESR) or serum C-reactive protein ( CRP) suggests vacsulitic urticaria
• urinalysis
• limited chemistry panel
• antinuclear antibodies ( ANA)
• thyroid function studies
• routine lab testing generally not helpful [6]

• serum IgE levels may be elevated with allergen exposure

Radiology

• chest X-ray for urticaria of more than 6 weeks duration

Complications

• angioedema
• autoimmune disease may occur up to 10 years after onset of chronic urticaria - probably related more to a common etiology rather than a direct complication [8]

Differential-diagnosis

• (lesions lasting > 24 hours)
• erythema multiforme
• vasculitis

Management

• pharmacologic agents

• topical antipruritic lotions/creams
• histamine H1-antagonists

• hydroxyzine ( Atarax) 25-50 mg PO every 4-6 hours
• diphenhydramine ( Benadryl) 25-50 mg PO every 4-6 hours
• chlorpheniramine
• loratadine ( Claritin)
• fexofenadine ( Allegra)
• doxepin ( TCA with H1-antagonist activity)

• addition of H2-antagonist for treatment of chronic or recurrent urticaria

• can induce remission in 60-80% of patients
• cimetidine, ranitidine, famotidine [4]
• doxepin with both H1- & H2-antagonist properties is often useful in treatment of chronic urticaria

• leukotriene antagonist if no response to above

• monteleukast, zafirlukast [4]

• trial of calcium channel blocker [4]
• oral prednisone if very symptomatic [4]
• immumosuppressive agents may be necessary from chronic autoimmune urticaria

• methotrexate
• azathioprine
• cyclosporine [4]
• omalixumab ( Xolair) [7]

• antibiotics for H pylori infection [4]
• psychotherapy

• biofeedback
• stress relaxation

• transcutaneous electrical nerve stimulation ( TENS)
• pulsed ultraviolet actinotherapy
• experimental agents

• colchicine
• dapsone
• leukotriene inhibitors may be useful for treatment of chronic idiopathic urticaria

• urticarial reactions lasting longer than 24-48 hours should be biopsied to rule out vasculitis & erythema multiforme
• patient education

• avoid offending agent
• food is the most common cause of acute urticaria
• avoid NSAIDs (increased availability of arachidonate may worsen urticaria)
• etiology of chronic urticaria (> 6 weeks duration) is unlikely to be identified

More General Terms

• sign/symptom

Additional Terms

• angioneurotic edema; angioedema; atrophedema; Bannister's disease; Milton's disease; Quincke's disease; periodic or Quincke's edema; giant urticaria or hives; urticaria gigans, gigantea, or tuberosa.
• erythema multiforme
• food allergy
• hymenoptera (insect) sting
• mast cell
• urticaria pigmentosa (UP)
• vasculitis

References

1. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 829-39
2. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 910-12
3. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 25-27
4. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, American College of Physicians, Philadelphia 1998, 2006, 2009
5. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 322
6. Tarbox JA et al. Utility of routine laboratory testing in management of chronic urticaria/angioedema. Ann Allergy Asthma Immunol 2011 Sep; 107:239 PMID: [1]
7. Saini S et al. A randomized, placebo-controlled, dose-ranging study of single-dose omalizumab in patients with H1-antihistamine- refractory chronic idiopathic urticaria. J Allergy Clin Immunol 2011 Sep; 128:567 PMID: [2]
8. Journal Watch, May 11, 2012 Massachusetts Medical Society
   - Confino-Cohen R et al. Chronic urticaria and autoimmunity: Associations found in a large population study. J Allergy Clin Immunol 2012 May; 129:1307 PMID: [3]
9. National Guideline Clearinghouse
   - Management and diagnostic guidelines for urticaria and angio-oedema. (British Association of Dermatologists) ngc-guideline: [4]
   - Guidelines for evaluation and management of urticaria in adults and children. (British Association of Dermatologists) ngc-guideline: [5]

urticaria (hives)