URTICARIA
Urticaria is also known as hives/wheal/welts
Urticaria is a skin condition typically present with
erythematous pruritic plaque often accompanied by angioedema.
What are the types of urticaria?
Acute and chronic
What is acute and chronic urticaria?
Urticaria is considered acute when it has been present for
less than six weeks.
Chronic urticaria — Urticaria is considered chronic when it
is recurrent, with signs and symptoms recurring most days of the week, for six
weeks or longer.
Why the period of 6 weeks is considered?
The period of six weeks is somewhat arbitrary and simply
represents a timeframe in which new cases of urticaria usually resolve. More
than two-thirds of cases of new-onset urticaria prove to be self-limited
(acute).
What are the differences in appearance between acute and chronic?
Identical in appearance.
How common is urticaria?
Around 20 % of world population is affected by urticaria at some
point of life and occurs across the age spectrum.
What is the pathophysiology of urticaria?
Mast cells in the superficial dermis of skin and basophil
activation leading to release of chemical mediators like histamine that causes
itching and vasodilatory mediators cause urticaria.
Activation od mast cells in deeper dermis and subcutaneous
tissue cause angioedema.
What are the etiologies of acute urticaria?
IgE mediated:
Food
Drugs (antibiotics)
Insect venoms
Blood products
Latex
Non-IgE mediated:
Radiocontrast agents
Virus
Opiates
NSAIDs
What are some of the common viral and bacterial infections associated with urticaria?
Mycoplasma (responsive to Azithromycin and non-responsive to
antihistamine)
Streptococcal pharyngitis
UTI
HIV
Hepatitis B
Infectious mononucleosis
What are common parasitic infections causing urticaria?
Parasitic infections generally cause acute, self-limited
urticaria in association with prominent eosinophilia.
Infections with Ancylostoma, Strongyloides, Filaria,
Echinococcus, Trichinella, Toxocara, Fasciola, Schistosoma mansoni, and
Blastocystis hominis have all been associated with urticaria.
Ingestion of fish contaminated with the parasite Anisakis
simplex can also cause urticaria. Anisakis can be transmitted through the
ingestion of sushi.
Whether the red man syndrome caused by Vancomycin is IgE or non -IgE mediated urticaria?
Non-IgE
How NSAID cause urticaria?
NSAIDs cause urticaria in some individuals, presumably due
to underlying abnormalities in arachidonic acid metabolism. This form of NSAID
reaction is called a pseudoallergic reaction because the mechanism is
nonimmunologic.
A specific NSAID can also cause acute urticaria in patients
who are allergic to that one agent. These reactions are presumed to represent
true, immunologic allergy.
What is Scombroid syndrome?
The ingestion of poorly preserved fish (tuna in most cases,
but sometimes mackerel or sardines) containing large amounts of histamine may
cause acute symptoms that resemble those of an IgE-mediated allergic reaction
characterized by flushing, urticaria, diarrhea, headache, and sometimes
bronchospasm.
What is progesterone associated urticaria?
There are rare reports of progesterone-containing oral
contraceptives, hormone replacement therapy, or endogenous progesterone
associated with cyclic urticaria. The disorder is sometimes called autoimmune
progesterone dermatitis. Lesions usually appear during the second half of the
menstrual cycle and resolve with menstruation.
What are the causes of chronic urticaria?
What is the difference between a typical urticaria and urticaria associated with systemic disease?
What is cold urticaria?
Development of localized pruritus, erythema, and
urticaria/angioedema after exposure to a cold stimulus.
Total body exposure, as seen with swimming in cold water, can
cause massive release of vasoactive mediators, resulting in hypotension, loss
of consciousness, and even death if not promptly treated.
How do we diagnose cold urticaria?
The diagnosis is confirmed by challenge testing for an isomorphic
cold reaction by holding an ice cube in place on the patient's skin for
5 min.
In patients with cold urticaria, an urticarial lesion
develops about 10 min after removal of the ice cube and on rewarming of the
chilled skin.
What cause cold urticaria?
Cold urticaria can be associated with the presence of
cryoproteins such as cold agglutinins, cryoglobulins, cryofibrinogen, and the
Donath-Landsteiner antibody seen in secondary syphilis (paroxysmal cold
hemoglobinuria).
Cold urticaria has been associated with some viral
infections.
What is idiopathic cold urticaria?
The term idiopathic cold urticaria generally applies to
patients without abnormal circulating plasma proteins such as cryoglobulins.
What is cholinergic urticaria?
It is characterized by the onset of small, punctate pruritic
wheals surrounded by a prominent erythematous flare and associated with exercise,
hot showers, and sweating.
Once the patient cools down, the rash usually subsides in
30-60 min.
Occasionally, symptoms of more generalized cholinergic
stimulation, such as lacrimation, wheezing, salivation, and syncope, are
observed.
How does cholinergic urticaria occur?
These symptoms are mediated by cholinergic nerve fibers that
innervate the musculature via parasympathetic neurons and innervate the sweat glands
by cholinergic fibers that travel with the sympathetic nerves. There has been
associated histamine release.
What is dermatographism?
The ability to write on skin, dermatographism (also called
dermographism or urticaria factitia ) may occur as an isolated disorder or may
accompany chronic urticaria or other physical urticaria.
How to diagnosis?
It can be diagnosed by observing the skin after stroking it
with a tongue depressor. In patients with dermatographism, a linear response
occurs secondary to reflex vasoconstriction, followed by pruritus, erythema,
and a linear flare caused by secondary dilation of the vessel and extravasation
of plasma.
What is pressure induced urticaria and angioedema?
Urticaria or angioedema in the area of pressure application.
It differs from other forms of physical urticaria in that it
occurs after 4-6 hours of pressure application.
It can either present with pruritis or without pruritis and
only edema.
Symptoms occur at the site of tight clothing: foot swelling
after walking; and buttock swelling after sitting for few hours.
How do we confirm a diagnosis of pressure urticaria?
The diagnosis is confirmed by challenge testing in which
pressure is applied perpendicular to the skin. This is often done with a sling
attached to a 10-pound weight that is placed over the patient's arm for 20 min.
What is solar urticaria?
It is a rare disorder in which urticaria develops within
minutes of direct sun exposure.
Typically, pruritus occurs first, in approximately 30 sec, followed
by edema confined to the light-exposed area and surrounded by a prominent
erythematous zone.
The lesions usually disappear within 1-3 hour after cessation
of sun exposure.
When large areas of the body are exposed, systemic symptoms
may occur, including hypotension and wheezing.
Solar urticaria has been classified into 6 types, depending
on the wavelength of light that induces skin lesions.
The rare inborn error of metabolism erythropoietic
protoporphyria can be confused with solar urticaria because of the development
of itching and burning of exposed skin immediately after sun exposure.
In erythropoietic protoporphyria, fluorescence of
ultraviolet-irradiated red blood cells can be demonstrated, and protoporphyrin
are found in the urine.
What is aquagenic urticaria?
It is characterized by small wheals after contact with water regardless of temperature of water.What is the most common cause of chronic urticaria?
Chronic idiopathic urticaria
It is often associated with normal routine lab values
without evidence of systemic disease.
Is there any association of chronic urticaria and thyroid
disease?
Chronic urticaria is increasingly associated with the
presence of antithyroid antibodies. Affected patients generally have antibodies
to thyroglobulin or a microsomally derived antigen (peroxidase), even if they
are euthyroid.
The incidence of elevated thyroid antibodies in patients
with chronic urticaria is approximately 12%, compared with 3–6% in the general
population.
However, the role of these thyroid antibodies is not clear.
What is autologous serum skin test?
When serum from chronic urticaria patients is intradermally injected into their skin, a significant wheal and flare reaction develops.Such patients frequently have a complement-activating IgG
antibody directed against the α subunit of the IgE receptor that can cross-link
the IgE receptor (α subunit) and degranulate mast cells and basophils.
An additional 5–10% of patients with chronic urticaria have anti-IgE
antibodies rather than an anti–IgE receptor antibody.
About 35-40% of patients of chronic urticaria have a
positive autologous serum skin test.
How to diagnose urticaria?
Diagnosis of both urticaria (acute and chronic) is clinical.
What are history that should be asked?
History of drug and food ingestion which are the most common
causes of urticaria should be taken,
History of viral infections.
Past h/o similar illness
Accompanying symptoms of chest tightness or difficulty
breathing, hoarse voice or throat tightness, nausea, vomiting, crampy abdominal
pain, lightheadedness, and other symptoms of anaphylaxis.
Any symptoms s/o systematic illness- fever, myalgia, weight
loss, arthralgias, arthritis, or bone pain.
What are the clinical features of urticaria?
Urticaria are transient, erythematous, pruritic raised
wheals that may become tense and painful.
Multiple lesions may coalesce and form polymorphous, serpiginous,
or annular lesions.
Individual lesions usually last 20 min to 3 hour and rarely
more than 24 hr. The lesions often disappear, only to reappear at another site.
Angioedema involves the deeper subcutaneous tissues in
locations such as the eyelids, lips, tongue, genitals, dorsum of the hands or
feet, or wall of the gastrointestinal (GI) tract.
Patients
with delayed urticaria 3-6 hr after a meal consisting of mammalian meat should
be evaluated for IgE to galactose-α-1,3-galactose (“alpha-gal”), a carbohydrate
allergen.
Skin and aeroallergen testing are not usually necessary.
Autoimmune are rare causes of chronic urticaria and investigations
are done only in cases of high suspicion.
What basic tests can be done if we suspect other causes of urticaria?
CBC, ESR, urine RME, LFT and thyroid antibody testing.
In cases of eosinophilia, stool testing can be done for
parasites.
Some specific diagnostic testing in cases of urticaria
How do we diagnose urticaria caused by mastocytosis?
Clinical effects of mast cell activation are common,
including pruritus, flushing, urtication, abdominal pain, nausea, and vomiting.
The diagnosis is confirmed by a bone marrow biopsy showing increased
numbers of spindle-shaped mast cells that express CD2 and CD25.
What is urticaria pigmentosa?
Urticaria pigmentosa is the most common skin manifestation
of mastocytosis. It may occur as an isolated skin finding. It appears as small,
yellow-tan to reddish brown macules or raised papules that urticate on
scratching (Darier sign). This sign can be masked by antihistamines
The diagnosis is confirmed by a skin biopsy that shows
increased numbers of dermal mast cells.
What is Muckle-Wells syndrome?
It is a rare Autosomal dominant disorder characterized by
recurrent urticaria like lesions with arthritis. It appears in adolescence with
progressive nerve deafness, fever and elevated ESR.
Familial cold autoinflammatory syndrome is characterized by
a cold-induced rash that has urticarial features but is rarely pruritic. Cold
exposure leads to additional symptoms such as conjunctivitis, sweating,
headache, and nausea. Patient longevity is usually normal.
What are the differential diagnosis?
Viral exanthem – non-pruritic
Auriculotemporal syndrome—non-pruritic
Sweet syndrome – painful rather than pruritic and long-lasting
plaques. Fever, arthralgia may be present.
Atopic dermatitis—ill-defined border with scaling and
persists for prolonged duration
Contact dermatitis -- present in area of contact, vesicle
may be present
Drug eruptions
How do we treat urticaria?
Acute urticaria in most cases resolve spontaneouslyChronic urticaria require treatments.
What are the commonly used pharmacological agents?
Histamine antagonist and steroids
Which antihistamines (H1 blockers) are prescribed?
Second generation antihistamines are usually preferred as they
are-
Non-sedating
Lack anticholinergic effects
Less drug interactions
Less frequent dosing
No data demonstrate that any specific agent is more
effective than another for the treatment of acute urticaria, although a few
studies in patients with chronic urticaria suggest that cetirizine levocetirizine
may be modestly more effective than other agents.
What is the role of H2 blocker antihistamines?
Some of the physicians prescribe combination of H1 and H2
blockers in cases of urticaria.
The 3-drug combination of H1 and H2 antihistamine with a
leukotriene receptor antagonist (montelukast) is helpful for many patients.
What is the role of steroids?
If hives persist after maximal H1 - and/or H2 -receptor
blockade has been achieved, a brief course of oral corticosteroids may be
considered, but long-term steroid use is best avoided.
OMALIZUMAB HAS BEEN APPROVED FOR REFRACTORY CHRONIC URTICARIA TREATMENT IN CHILDREN ABOVE 12 YEARS AND ADULT
How do we treat cold urticaria?
Cyproheptadine in divided doses is the drug of choice for
cold-induced urticaria.
How do we treat dermatographism?
Treatment of dermatographism consists of local skin care and
antihistamines; for severe symptoms, high doses may be needed.
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