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蕁麻疹
VS 吳青穎
Clerk 雲智謙.洪睿
2010/01/28
蕁麻(urtica)
 蕁麻科(Urticaceae)植物其葉子長著充滿毒液的刺毛，可保護自
己免於給草食動物吞食。如人的皮膚碰到毒毛就很不幸了，皮膚
馬上產生蜂蟄般的疼痛，還有浮腫的疹子，這種疹子即典型的蕁
麻疹。
 遠在公元前四世紀，蘇格拉底就已發現碰到蕁麻可以引起蕁麻疹。
蕁麻疹的英文病名為urticaria，urtica就是蕁麻的拉丁文名，
指的是碰到蕁麻後，皮膚疹子之似火燒灼般的疼痛感。
 我國古人也很早就發現了蕁麻的多種特性，在明《本草綱目毒草
類三十種》裡就提到了蕁麻：“蕁麻生汗寧府山野中，其莖有刺，
高二三尺。葉似花桑上有毛芒可畏，觸人如蜂蟄。”
蕁麻疹
 蕁麻疹是一種很常見的皮膚病，會使病人的皮膚出現
極癢的膨疹，有如蚊子叮了一般的腫塊，雖可自行消
退，但常反覆發生，來去有如風一般，故又俗稱「風
疹」
 另名 “風團”“風包”
outline
 Introduction
 Definition
 Pathogenesis
 Classification (type, subtype …)
Introduction (1)
 Urticaria, or hives, is a common disorder affecting up to
25 percent of the population
 The usual urticarial lesion is an intensely pruritic,
circumscribed, raised, erythematous plaque, often with
central pallor.
 Individual lesions may enlarge and coalesce with other
lesions, and then typically will disappear over a few hours
without leaving residual marks on the skin unless there is
damage from scratching
Introduction (2)
 The most common complaint of patients with urticaria is
pruritus that may cause difficulties with sleep or work.
Significant disability has been reported in the quality of
life of patients with chronic urticaria
 Urticaria is a process mediated by the cutaneous mast
cell in the superficial dermis. By comparison,
angioedema involves the deeper dermis and
subcutaneous tissues. Angioedema may be disfiguring if
it involves the face and lips, or life-threatening if airway
obstruction occurs from laryngeal edema or tongue
swelling.
小紅
367頁
Definition
 Urticaria is characterized by the sudden
appearance of wheals and/or angioedema
 Whereas 85 percent of children experience
urticaria in the absence of angioedema, 40
percent of adult patients with urticaria also
experience angioedema.
edema of the upper and mid dermis,  occur primarily in the lower
w/ dilatation of the postcapillary
dermis and the subcutis.
venules and lymphatic vessels of the
upper dermis.
a central swelling of variable size,
almost invariably surrounded by a
reflex erythema
associated itching or, sometimes,
burning sensation
a fleeting nature, w/ skin returning
to its normal appearance, usually
within 1–24 h
a sudden, pronounced swelling of
the lower dermis and subcutis
sometimes pain rather than
itching
resolution slower than wheals and
can take 72 h
frequent involvement below
mucous membranes
Morphology may be variable (1)
Morphology may be variable (2)
Morphology may be variable (3)
angioedema
angioedema
Pathogenesis
IgE-dependent
Physical
Foods
Medications
Stinging insects
Contact (animal saliva, latex)
Parasitic infection
Blood products (urticarial transfusion
reactions)
Dermatographism
Delayed pressure
Cold
Cholinergic
Vibratory
Aquagenic
Solar
Direct mast cell release
Complement-mediated
Opiates/narcotics
Muscle relaxants (succinylcholine,
curare)
Radiocontrast agents
Vancomycin
Infection (viral, bacterial)
Serum sickness
Transfusion reactions (distinct from IgE
mechanism)
Urticarial vasculitis
Hormone related
Arachidonic acid metabolism
Progesterone
Aspirin
Nonsteroidal antiinflammatory drugs
Etiology and diagnosis of urticaria, UpToDate
classification
Intravenous
administration
Aquagenic
urticaria
antithyroid
antibodies
Cold urticaria
Urticarial
vasculitis
Cholinergic
urticaria
Idiopathic
……
Delayed pressure
urticaria
……
acute
physical
chronic
Classification of urticaria on the basis of its
duration, frequency, and causes
EAACI/GA2LEN/EDF/WAO guideline: definition, classification and diagnosis of urticaria
Allergy 2009: 64: 1417–1426
 Acute urticaria:
 More than two-thirds of cases of urticaria are self-limited.
 defined as outbreaks of urticarial lesions that do not extend in
duration beyond six weeks.
 The lesions of acute urticaria are characterized by a rapid onset
and resolution within several hours and they can be recurrent
 A presumptive trigger such as a drug, food ingestion, insect sting,
or infection can occasionally be identified
 Chronic urticaria:
 defined by the presence of hives, usually on most days of the
week, for a duration of longer than six weeks.
 However, in 80 to 90 percent of adults and children with chronic
urticaria, no external cause can be identified
 About 40 percent of patients with chronic urticaria have
associated angioedema, which typically affects the lips, cheeks,
and periorbital areas of the face, extremities, and genitals
Epidemiology, healthcare, resources, use and clinical features of different types of urticaria.
Alergológica 2005
*Foods and additives
 Milk, egg, peanuts, nuts, soy, and wheat are the most
common agents to cause generalized urticaria in
children.
 In adults, fish, shellfish, tree nuts, and peanuts are
most often implicated
*DERMOGRAPHISM
 means to ''write on the skin.''
 rapid onset of a wheal and flare reaction after firm
stroking, scratching, or the application of pressure
 most common of the physical urticarias
Clinical findings?
IgE and IgE receptor related?
 Atopic Diathesis
 w/ family Hx of asthma, rhinitis, or eczema are
presumed to be IgE dependent.
 However, infrequently accompanies an
exacerbation of asthma, rhinitis, or eczema.
 Specific Antigen Sensitivity
 Food: shellfish, nuts, milk, eggs, and chocolate
 Drug: penicillin
Physical Urticaria/Angioedema?
 Dermographism（skin writing）
 Pressure Urticaria
 Vibratory Angioedema
 Cold Urticaria
 Cholinergic Urticaria
 Local Heat Urticaria
 Solar Urticaria
 Exercise-Induced Anaphylaxis
 Adrenergic Urticaria
other
 Contact Urticaria
 Papular Urticaria
 Urticaria/Angioedema
Mediated by Bradykinin,
the Complement System,
or Other Effector
Mechanisms
 Urticarial Vasculitis
 Serum Sickness
 Reactions to the
Administration of Blood
Products
 Infections
 Urticaria/Angioedema
after Direct Mast Cell
Degranulation
 Urticaria/Angioedema
Related to Abnormalities
of Arachidonic Acid
Metabolism
 Chronic Idiopathic Urticaria
and Idiopathic
Angioedema
 Miscellaneous
Systemic d’s that may induce urticaria
 Urticaria or urticarial-like lesions may occasionally be a
presenting or early feature of a systemic disorder. With
the exception of autoimmune thyroid disease, these
disorders are rare.
 systemic s/s: fever, arthralgias, arthritis, weight changes, bone
pain, or lymphadenopathy
 painful urticarial, long-lasting (longer than 36 to 48 hours), or
appear ecchymotic, as these are characteristics of vasculitic
lesions
 residual ecchymosis or hyperpigmentation upon resolution
 Urticaria that are refractory to treatment
Systemic d’s that may induce urticaria
 Autoimmune thyroid disease
 Systemic lupus erythematosus
 Cryoglobulinemia
 Urticarial vasculitis
 Mastocytosis
 Schnitzler's syndrome
 Familial cold autoinflammatory syndrome
 Muckle-Wells syndrome
 Malignancy