Download C.T. diseases

Objectives
Describe the morphology of urticaria and
angioedema.
•
• Develop an initial treatment plan for a
patient with acute or chronic urticaria and
angioedema.
• Recognize the signs and symptoms of
anaphylaxis
urticaria
• A hive or wheal is a circumscribed,
erythematous or white, nonpitting, edematous,
usually pruritic plaque that changes in size and
shape by peripheral extension or regression
during the few hours or days. The edematous,
central area (wheal) can be pale in comparison
to the erythematous surrounding area (flare).
Lesions vary in size
from the 2- to 4-mm
edematous papules of
cholinergic urticaria to
giant hives, a single
lesion of which may
cover an extremity.
They may be round or
oval; when confluent,
they become
polycyclic
Hives itch.
The intensity
varies, and
some
patients with
a widespread
eruption may
experience
little itching.
Pathophysiology
Immunologic Urticaria: antigen binds to IgE on the mast cell
surface causing degranulation, which results in release of
histamine
• Histamine binds to H1 and H2 receptors to cause arteriolar
dilatation, venous constriction and increased capillary
permeability.
Non-Immunologic Urticaria: not dependent on the binding of
IgE receptors
• For example, aspirin may induce histamine release through a
pharmacologic mechanism where its effect on arachidonic acid
metabolism causes a release of histamine from mast cells. •
Physical stimuli may induce histamine release through direct mast
cell degranulation.
Urticaria results
from release of
histamine,
bradykinin,
Leukotriene C4
Prostaglandin D2
Among others
Etiologic Classification of Urticaria
Foods and Food additives
Drugs
Infections
Chronic bacterial infections (e.g., sinus, dental, chest, gallbladder, urinary tract), fungal infections (e.g.,
dermatophytosis, candidiasis), viral infections (e.g., hepatiti B), protozoal and helminth infections
(e.g., intestinal worms, malaria)
Inhalants
Pollens, mold spores, animal dander, house dust, aerosols, volatile chemicals
Internal disease
Eg, systemic lupus erythematosus, hyperthyroidism, autoimmune thyroid disease
Physical stimuli (physical urticarias)
Dermographism, pressure urticaria, cholinergic urticaria, exercise-induced anaphylactic syndrome,
solar urticaria, cold urticaria, heat urticaria, vibratory urticaria, water (aquagenic) urticaria
Nonimmunologic contact urticaria
Plants (e.g., nettles)
Immunologic or uncertain mechanism contact urticaria
Ammonium persulfate used in hair bleaches, chemicals, foods, textiles, wood, saliva, cosmetics,
perfumes, bacitracin
Skin diseases
Urticaria pigmentosa (mastocytosis), dermatitis herpetiformis, pemphigoid.
Hormones
Pregnancy, premenstrual flare-ups (progesterone)
Nonimmunologic contact urticaria
Plants (nettles)
Patients who have a history of hives lasting for 6 or
more weeks are classified as having
chronic urticaria (CU). The etiology is often
unclear. The morphology is similar to that of
acute urticaria
• Urticaria—Evaluation and Management
• History and physical examination
Ask the patient if he or she knows what causes the hives. In many
instances, the patient will have determined the cause.
• Stroke the arm to test for dermographism.
• If the etiology is not determined by history, physical examination, and
stroking the arm, order laboratory tests.
• Laboratory tests
• Order CBC with differential, erythrocyte sedimentation rate (ESR), liver
function tests (LFTs), and urinalysis.
• The history and physical examination may provide evidence that
warrants additional tests. Consider testing for hepatitis A, B, C; infectious
mononucleosis; thyroid function tests; thyroid antibodies; and
antinuclear antibodies (ANAs).
• Consider allergen testing
• Skin tests: foods, drugs, aeroallergens, insect venom, natural rubber.
• Management
•
•
•
•
Avoid specific allergens.
Treat with oral H1 antagonists.
Add H2 antagonists for resistant cases.
Anaphylaxis—subcutaneous epinephrine with or
without parenteral H1 and H2 antihistamines (e.g.,
50 mg of diphenhydramine and 50 mg of ranitidine).
Systemic corticosteroids are sometimes useful.
• Systemic steroids (short courses) may be used to
provide temporary relief.
• Leukotriene receptor antagonists—zafirlukast and
montelukast
• Cyclosporine
Angioedema
• is a hivelike swelling caused by increased
vascular permeability in the subcutaneous
tissue of the skin and mucosa and the
submucosal layers of the respiratory and GI
tracts. A similar reaction occurs in the dermis
with hives.
• Hives and angioedema commonly occur
simultaneously and can have the same
etiology.
Hereditary angioedema results
from a lack of functional C1
esterase inhibitor.
Hereditary angioedema
(inherited C1 inhibitor
deficiency) is transmitted as an
autosomal dominant trait and
is due to mutations in the C1
inhibitor (C1 INH) gene.
Angioedema
involving much of
the skin surface.
The wheals are
massive on the
back and
shoulder
• Acquired angioedema (AAE) can be
immunologic, nonimmunologic, or idiopathic.
• It is usually caused by allergy and occurs
together with other allergic symptoms
and urticaria.
• It can also occur as a side effect to certain
medications, particularly ACE inhibitors.
• It is characterized by repetitive episodes of
swelling, frequently of the face, lips, tongue,
limbs, and genitals. Edema of the
gastrointestinal mucosa typically leads to
severe abdominal pain; in the upper
• Diagnostic Features That Should Prompt
Investigations for C1 Inhibitor Deficiency
• Recurrent
• >24 hr
• Nonpruritic
• Nonresponsive to antihistamines
• Serpiginous rash
• No urticaria
• Unexplained abdominal pain (recurrent,
colicky)
• Family history
• hereditary angioedema,
• It does not respond to antihistamines,
corticosteroids, or epinephrine.
• Acute treatment consists of C1-INH
concentrate from donor blood, which must be
administered intravenously.
• In an emergency, fresh frozen blood plasma,
which also contains C1-INH, can also be used.
• Future attacks of hereditary angioedema can
be prevented by the use of androgens such
as danazol, oxandrolone or methyltestosteron
• Angioedema and/or urticaria may be the
cutaneous presentation of anaphylaxis, so
assessment of the respiratory and
cardiovascular systems is vital
• First-line therapy for anaphylaxis includes
epinephrine, IV fluids and oxygen
Administer 0.3-0.5ml in 1:1000 epinephrine
dilution IM repeating every 10-20min as
necessary
• Make sure airway is patent or else
intubation may be emergently necessary
Take Home Points
• Urticaria (hives) is a vascular reaction of the
skin characterized by wheals surrounded by a
red halo or flare.
• Urticaria is classified as acute or chronic.
• Acute urticaria is defined as periodic
outbreaks of urticarial lesions that resolve
within six weeks.
• Over 50% of chronic urticaria is idiopathic.
• Oral H1 antihistamines are first-line
treatment for acute and chronic urticaria
Remember to ask about symptoms of
anaphylaxis, including: chest tightness or
difficulty breathing, hoarse voice or throat
tightness, nausea, vomiting, abdominal pain,
lightheadedness