Urticaria is a skin
that accompanies many .
It is a relatively common disorder caused by localized
degranulation, with resultant dermal venular hyperpermeability culminating
in pruritic wheals. Mostly results from an antigen-induced ( ,
) release of
and other vasoactive amines via sensitization with specific
antibodies. Most individual lesions develop and fade within 24 hours.
Allergic skin diseases such as urticaria and
as well as atopic are not clearly
defined as true allergic diseases. Urticaria and angioedema are both due
to excessive mast cell activity in the skin. Chronic urticaria and angioedema
are seldom due to a definable mechanism (as
is the case with all allergies) but, when determined, is generally due
to a , or
Classification of Urticaria
Urticaria and Urticaria with an Identifiable Cause
Urticaria (cold urticaria)
Atopic dermatitis is associated with high serum
IgE levels as well as a history of atopic disease ( ,
, etc.). Unfortunately, management is
difficult since the medications classically associated with treatment
of allergic diseases (i.e. )
have little effect in these patients.
A common form of hives is dermatographism, which occurs in 5% of the population.
The hives are caused by a constant stroking or rubbing of the skin and
often occur following scratching, or when tight-fitting clothes rub the
Common Causes of Urticaria :
for example: ,