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CQCMAY 26, 2009
KEVIN POLSLEY, MDMEDICINE PEDIATRICS PGY2
It Itches!
Clinic Visit
CJ is a 17 year old maleClinic visit for school physicalPreviously healthy with no significant PMHComplains of itchy red rashRash has been present for the past six weeksHe has noticed several exacerbating factors:
Tight clothing Cold weather Exercise
The rash comes and goes quickly
Clinic Visit Continued
ROS, PMH, FHx, SHx all negativeExam:
Vitals normal Lungs CTA Heart RRR, no murmur Abdomen soft, ND/NT, no organomegaly Skin: normal, then…
Clinical Question:
What is the significance of urticaria that has been present
for 6 weeks?
Urticaria
Recurrent, generalized, erythematous, pruriticCircumscribed borders, blanch with pressureIncidence: 15% to 25%Wheal (edema) and flare (erythema)Acute: less than 6 weeks durationMorbidity:
swelling, itching, and pain impact on mobility, self-image, and social interactions
Strongly associated with angioedema (40%)
Differential Diagnosis
Viral exanthemsAtopic dermatitisContact dermatitisErythema multiformePityriasis roseaMastocytosis/MastocytomaUrticaria pigmentosa
Mechanisms
Immune mediated (IgE hypersensitivity)Complement mediatedNon-immune mediated (degranulation of mast
cells by something other than IgE)Autoimmune mediatedUnkown
Idiopathic Infection Medications Systemic illnesses (some)
Acute Urticaria
More common in young childrenSpecific cause is more likely to be identifiedFrequently attributed to viral infections,
medications, or foods Younger children: egg, milk, soy, peanut, and wheat Older children: fish, seafood, nuts, and peanuts Food-induced contact urticaria with atopic dermatitis
Transient natureExtensive assessment usually unnecessary
Chronic Urticaria
More common in adultsCause is determined in less than 20% of
casesCauses include:
Physical urticaria Autoimmune urticaria Medications
May be sign of systemic illness: Thyroid dysfunction Vasculitis Connective tissue disease Lymphoproliferative disorders
Chronic Urticaria: Physical
Dermographism: 2-5% of general population IgE mediated? No allergen identified No systemic symptoms
Cholinergic Precipitated by heat, exertion, and emotional factors May have systemic symptoms (wheezing, angioedema) Mast cell activation
ColdDelayed PressureSolar (less common)Aquagenic (uncommon)
Dermographism on Flickr
Chronic Urticaria: Systemic Illness
Autoimmune thyroid disease Hashimotos > Graves Mechanism unknown 19% have abnormal TFTs; unclear significance
Vasculitis SLE
Malignancy Lymphoproliferative disorders Sweet's syndrome (acute febrile neutrophilic
dermatosis) Cryoglobulinemia
Buttocks and LEs; HCV infectionH pylori gastritis
Evaluation: History
Viral infectionRecent insect bites or stingsBlood transfusionSuspected foodsSkin contact to foreign material, heat, cold,
waterHyper/Hypothyroid symptomsMedications (Alcohol, NSAIDs, opiates, ACEs)Other symptoms such as lip swelling
(angioedema)
Evaluation: Exam
Dermographism: linear whealsCholinergic: small wheals surrounded by
erythemaSolar or cold: limited to exposed areasPressure or urticarial vasculitis: wheals on
LEsCold provocation test:
Placing an ice cube to the forearm for 4 minutes Development of urticaria during rewarming
Warm arm bath
Evaluation: Labs
Acute: allergen testing as directed by history
Chronic: directed by findings ANA TFTs and anti-thyroid antibodies CBC with differential ESR Meta-analysis: no correlation between number of
tests performed and number of diagnoses identified
Treatment
Avoidance of triggersFirst line therapy are anti-histaminesH1 blockers: 85% of cutaneous receptors
1st gen: diphenhydramine, hydroxyzine, chlorpheniramine 2nd gen: Loratadine, cetirizine, desloratatine,
fexofenadineH2 blockers: 15% of cutaneous receptors
Ranitidine or cimetidine Mizolastine (Europe)
Combination of above medications if necessary 2nd generation in the morning, 1st generation at night
Alternative Treatments
Leukotriene receptor antagonists: Improve hives and swelling compared with placebo RCT: desloratadine vs. montelukast vs. both showed
no benefit with combo therapy vs. desloratadine monotherapy
Corticosteroids (lowest effective dose) Urticarial vasculitis Delayed pressure urticaria Alternate day dosing
Cyclosporine Low dose (2.5 – 3 mg/kg/day)
Ketotifen (mast cell stabilizer)
References
Grattan, Clive. “Autoimmune Urticaria.” Immunol Allergy Clin North Am., 2004 May;24(2):163-81.
Kaplan, Allen. “Clinical practice. Chronic urticaria and angioedema.” N Engl J Med., 2002 Jan 17;346(3):175-9.
Rumbryt, Jeffrey. “Chronic Urticaria and Thyroid Disease.” Immunol Allergy Clin North Am., 2004 May;24(2):215-223.
Dice, John. “Physical Urticaria.” Immunol Allergy Clin North Am., 2004 May;24(2):225-246.
Zuberbier, T. “Urticaria.” Allergy. 2003 Dec;58(12):1224-34. Muller, BA. “Urticaria and angioedema: a practical approach.” Am
Fam Physician. 2004 Mar 1;69(5):1123-8. Baxi, Sachin. “Urticaria and Angioedema.” Immunol Allergy Clin
North Am., 2004 May;24(2):353-367.
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