Urticaria (Hives)
Rule out Papular urticaria
(aka 'bug bites') - usually grouped or linear in a 'breakfast, lunch, dinner' pattern.
Rule out Urticaria pigmentosa
(cutaneous mastocytosis)- localized tan 'mole' that swells and itches (urticates) when stimulated, does not move.
Genetic causes
Autosomal dominant RARE Include the following Hereditary angioedema cholinergic urticarial amyloidosis of kidney familial cold urticarial vibratory urticaria
Hives- possible chronic causes (> 6 weeks)
Chronic spontaneous urticaria has also been associated with: Chronic underlying infection, eg Helicobacter pylori, bowel parasites Chronic autoimmune disease, eg systemic lupus erythematosus, thyroid disease, celiac disease, vitiligo and others Majority of cases are idiopathic
Wheals in chronic spontaneous urticaria may be aggravated by:
Heat Tight clothing Drug pseudoallergy—aspirin, nonsteroidal anti-inflammatory drugs, opiates Food pseudoallergy—salicylates, azo dye food colouring agents such as tartrazine (102), benzoate preservatives (210-220) and other food additives
Urticaria pathophysiology
Histamine release is the underlying mechanism for this eruption Wheals are due to release of chemical mediators from tissue mast cells and circulating basophils. These chemical mediators include histamine, platelet-activating factor and cytokines. The mediators activate sensory nerves and cause dilation of blood vessels and leakage of fluid into surrounding tissues. Bradykinin release causes angioedema. Can induce serum-sickness syndrome in extreme cases
Other things to rule out:
If have chronic hives should rule out the physical urticarias which are dermographism, pressure urticaria, cholinergic urticaria and cold urticarial Treat identified chronic infections such as H pylori (ROS for GERD) Avoid aspirin, opiates and nonsteroidal anti-inflammatory drugs Minimize dietary pseudoallergens for a trial period of at least 3 weeks. Avoid known allergens that have been confirmed by positive specific IgE/skin prick tests if these have clinical relevance for urticaria. Cool the affected area with a fan, cold flannel, ice pack or soothing moisturizing lotion.
Rule out Urticarial stage of bullous pemphigoid.
No blisters in urticaria.
Omalizumab
Omalizumab (Xolair) is a monoclonal antibody directed against IgE, with low toxicity. (< 1% risk of anaphylaxis so must also have Rx for epipen)- very helpful, new drug
treatment with omalizumab or cyclosporine
There is good evidence to support treatment with omalizumab or cyclosporine, which each have a 65% response rate in antihistamine-resistant patients.
Characteristic of hives:
They blanch
Urticaria diagnosis
Usually can diagnosis clinically based on exam and history May need biopsy to rule out urticarial vasculitis if unsure or vague history If diagnosis of acute urticarial, treat and monitor, usually self-limiting If the hives continue to return or are resistant to treatment for > 6 weeks they are now chronic and need to do labs: CBC, CMP, ANA, C3, C4, TSH, thyroid ABs, ESR, hepatitis panel, UA
Chronic spontaneous urticaria
affects 0.5-2% of the population; in some series, two-thirds are women
Urticarial wheals size:
can be a few millimeters or several centimeters in diameter, colored white or red. Each wheal may last a few minutes or several hours, and may change shape. Wheals may be round, or form rings, a map-like pattern or giant patches.
Rule out Urticarial vasculitis
causes persistent urticaria-like plaques that last more than 24 hours and resolve with bruising, non-blanching, more painful than itchy. Biopsy reveals leukocytoclastic vasculitis, (needs extensive work up)
Angioedema
deeper swelling within the skin or mucous membranes, and -may be itchy or painful but is often asymptomatic. -more often localized. It commonly affects the face (especially eyelids and perioral sites), hands, feet and genitalia. It may involve tongue, uvula, soft palate, or larynx. If present, need to Rx epipen for risk of anaphylaxis
Cyclosporine
is a calcineurin inhibitor, with potential serious side effects (eg may increase blood pressure and reduce renal function). It is a short-term medication (3-6 months) due to increased risk of cancer Need baseline CMP, CBC, Mg, FLP and continued monitoring Suppresses immunity, so stop if ill or febrile
Inducible acute urticaria
is fairly common and at least 20% of the population at some point in life Can occur at any age Are more common in patients with atopic dermatitis Self-limiting
Chronic treatment
managed by dermatology Antihistamines (Zyrtec can still cause drowsiness in 15% of population, so may use Claritin 2 tabs bid max) Doxepin (10 mg -40 mg HS) Singulair 10 mg HS Prednisone (only for severe flares, if on over 1 month, need calcium and vit D supplementation to prevent osteoporosis) Cyclosporine (3mg/kg/day divided bid and taper down as able) Cellcept (less effective, but less side effects then cyclosporine) Xolair (monthly injection in the office)
A wheal is a
superficial skin-colored or pale skin swelling, usually surrounded by erythema lasting from a few minutes to 24 hours. Usually very itchy, it may have a burning sensation.
Treatment for acute urticaria
usually self-limiting - Stop NSAIDs and any other suspected drug for 3 month trial if applicable (ace-inhibitors, arbs, HCTZ are common ones, multivitamins, energy drinks) Antihistamines (2nd generation are non-drowsy, 1st gen cross BBB and cause drowsiness -Benadryl, hydroxyzine, doxepin) Start hypoallergenic products (Dove soap, free and clear detergent) Prednisone taper (60mg/40mg/20mg over 3 weeks) Topicals are not very helpful, other than ice, cool baths Allergist referral to rule out exogenous cause if persistent -- oral second-generation antihistamine chosen from the list below. If the standard dose (eg 10 mg for cetirizine) is not effective, the dose can be increased up to fourfold (eg 20 mg bid). Cetirizine Loratidine Fexofenadine Desloratadine Levocetirizine May add nightly Singular (may cause bed-wetting in young children)
Urticaria is characterized by
wheals (hives) or angioedema (swellings, in 10%) or both (in 40%).