WILLIAM TOWNSEND, OD
spring approaches, healthcare providers expect to encounter patients complaining
of the symptoms of seasonal allergy. But another subset of allergy sufferers
have perennial allergies and must deal with the signs and symptoms for most of
the year. Managing their disease differs from managing seasonal allergy.
Defining Perennial Allergy
Perennial allergies occur for more than nine months of the year.
Individuals who have year-round allergies often experience seasonal exacerbations
during periods of peak pollen concentration.
Indoor allergens such as animal dander, molds and cockroach droppings
trigger perennial allergies, with the most common cause from dust mite droppings.
Dust mites live in carpets, bedding, pillows and dust, and their droppings contain
undigested proteins that trigger allergies.
People aren't allergic to animal hair, but to protein derived
from animal saliva or from dead skin flakes (dander). Patients may inhale these
proteins or transfer them by touch directly to their skin or eyes.
Managing Perennial Allergy
History Obtaining a good history is vital in managing
this patient group. Include details of symptoms and the seasons during which they're
most prevalent. Question such individuals about their home and work environments.
Ask whether they have any type of pet in the home or yard, and whether the pet has
access to the bedroom. Also ask about the type of floors and floor coverings in
the home. Other important information includes the frequency of washing sheets and
blankets, frequency of washing pets and specific types of vacuum cleaners used in
cleaning the house.
Reduce Triggers The single best means of reducing
or eradicating dust mites is by lowering humidity levels to less than 50 percent.
Patients should also wash bed linens and mattress pads weekly in hot water. In damp
climates, they should encase new pillows and mattresses in zippered, allergen-proof
covers (Nationalallergysupply.com or AlerG
.com). The ideal "mite-proof home"
would have hardwood or tiled floors with minimal floor coverings. Periodic steam
cleaning and frequent high-filtration vacuuming can help minimize mite allergen
in carpeted homes.
As with dust mites, pet owners are better off if they have hardwood
or tiled floors. In homes with carpet, HEPA vacuum cleaning is also an effective
means of reducing animal dander. Advise patients to wash pet bedding every week.
We also suggest keeping pets out of the bedroom (good luck). Moving the animal outside
isn't as effective as you might assume homes with pets that stay in the yard
still have high levels of allergen inside.
Medications To effectively treat and prevent signs
and symptoms of perennial allergy, it's critical to prevent degranulation of mast
cells. Combination mast cell stabilizers such as Zaditor (Novartis Ophthalmics),
Optivar (MedPointe Pharmaceuticals), Elestat (Allergan) and Patanol (Alcon) are
powerful blockers of histamine-1 sites and also offer varying degrees of mast cell
stabilization. Brockman et al (2003) and others have shown that Patanol is the most
efficacious mast cell stabilizer in this group.
Topical, site-specific steroids can quiet the angry allergic eye,
but long-term use of these compounds still carries the risk of steroid-related complications.
You can also refer patients to an allergist or otolaryngologist for immunotherapy
Perennial allergic eye disease is becoming increasingly prevalent
in our society. It's imperative that we correctly diagnose and manage this condition
to improve the quality of life for our affected patients.
For references, visit
click on document #124.
Dr. Townsend is in private
practice in Canyon, Texas, and is a consultant at the Amarillo VA Medical Center.
E-mail him at firstname.lastname@example.org.
Contact Lens Spectrum, Issue: March 2006