ALLERGENIC MOLDS
MOLD ALLERGIES
Along with pollens from
trees, grasses, and
weeds, molds are an
important cause of
seasonal allergic
rhinitis. People
allergic to molds may
have symptoms from
spring to late fall. The
mold season often peaks
from July to late
summer. Unlike pollens,
molds may persist after
the first killing frost.
Some can grow at
subfreezing
temperatures, but most
become dormant. Snow
cover lowers the outdoor
mold count dramatically
but does not kill molds.
After the spring thaw,
molds thrive on the
vegetation that has been
killed by the winter
cold.
In the warmest areas of
the United States,
however, molds thrive
all year and can cause
year-round (perennial)
allergic problems. In
addition, molds growing
indoors can cause
perennial allergic
rhinitis even in the
coldest climates.
When inhaled,
microscopic fungal
spores or, sometimes,
fragments of fungi may
cause allergic rhinitis.
Because they are so
small, mold spores may
evade the protective
mechanisms of the nose
and upper respiratory
tract to reach the
lungs.
In a small number of
people, symptoms of mold
allergy may be brought
on or worsened by eating
certain foods, such as
cheeses, processed with
fungi. Occasionally,
mushrooms, dried fruits,
and foods containing
yeast, soy sauce, or
vinegar will produce
allergic symptoms. There
is no known
relationship, however,
between a respiratory
allergy to the mold
Penicillium and an
allergy to the drug
penicillin, made from
the mold.
Which molds are
allergenic?
Like pollens, mold
spores are important
airborne allergens only
if they are abundant,
easily carried by air
currents, and allergenic
in their chemical
makeup. Found almost
everywhere, mold spores
in some areas are so
numerous they often
outnumber the pollens in
the air. Fortunately,
however, only a few
dozen different types
are significant
allergens.
In general, Alternaria
and Cladosporium (Hormodendrum)
are the molds most
commonly found both
indoors and outdoors
throughout the United
States. Aspergillus,
Penicillium,
Helminthosporium,
Epicoccum, Fusarium,
Mucor, Rhizopus, and
Aureobasidium (Pullularia)
are also common.
Mold counts
Similar to pollen
counts, mold counts may
suggest the types and
relative quantities of
fungi present at a
certain time and place.
For several reasons,
however, these counts
probably cannot be used
as a constant guide for
daily activities. One
reason is that the
number and types of
spores actually present
in the mold count may
have changed
considerably in 24 hours
because weather and
spore dispersal are
directly related. Many
of the common allergenic
molds are of the dry
spore type--they release
their spores during dry,
windy weather. Other
fungi need high
humidity, fog, or dew to
release their spores.
Although rain washes
many larger spores out
of the air, it also
causes some smaller
spores to be shot into
the air.
In addition to the
effect of day-to-day
weather changes on mold
counts, spore
populations may also
differ between day and
night. Day favors
dispersal by dry spore
types and night favors
wet spore types.
Other mold-related
disorders
Fungi or microorganisms
related to them may
cause other health
problems similar to
allergic diseases. Some
kinds of Aspergillus may
cause several different
illnesses, including
both infections and
allergy. These fungi may
lodge in the airways or
a distant part of the
lung and grow until they
form a compact sphere
known as a "fungus
ball." In people with
lung damage or serious
underlying illnesses,
Aspergillus may grasp
the opportunity to
invade the lungs or the
whole body.
In some individuals,
exposure to these fungi
also can lead to asthma
or to a lung disease
resembling severe
inflammatory asthma
called allergic
bronchopulmonary
aspergillosis. This
latter condition, which
occurs only in a
minority of people with
asthma, is characterized
by wheezing, low-grade
fever, and coughing up
of brown-flecked masses
or mucus plugs. Skin
testing, blood tests,
X-rays, and examination
of the sputum for fungi
can help establish the
diagnosis.
Corticosteroid drugs are
usually effective in
treating this reaction;
immunotherapy (allergy
shots) is not helpful
Call 678-580-0132
