Background: Allergy to natural rubber latex is increasingly
common and serious in children and adults. Latex is the milky fluid derived
from the lactiferous cells of the rubber tree, Hevea brasiliensis. It
is composed primarily of cis-1,4-polyisoprene, a benign organic
polymer that confers most of the strength and elasticity of latex. It also
contains a large variety of sugars, lipids, nucleic acids, and highly
More than 200 polypeptides have been isolated from latex. Latex proteins
vary in their allergenic potential. Protein content varies with harvest
location and manufacturing process. Basic knowledge of the manufacturing
processes aids in understanding the medical problems related to latex
Allergies affect more than 50 million people in the United States -- the poor souls who sniffle, sneeze, and get all clogged up when face to face with the allergen (or allergens) that set them off.
For many, allergies are seasonal and mild, requiring nothing more than getting extra tissue or taking a decongestant occasionally. For others, the allergy is to a known food, and as long as they avoid the food, no problem.
But for legions of others adults, allergies are so severe it interferes with their...
Freshly harvested latex from Malaysia, Indonesia, Thailand, and South
America is treated with ammonia and other preservatives to prevent
deterioration during transport to factories. Latex is treated with antioxidants
and accelerators including thiurams, carbamates, and mercaptobenzothiazoles. It
is then shaped into the desired object and vulcanized to produce disulfide
cross-linking of latex molecules.
After being dried and rinsed to reduce proteins and impurities, the product
frequently is dry-lubricated with cornstarch or talc powder. Powder particles
rapidly adsorb residual latex proteins; other proteins remain in soluble form
on the surface of finished products.
Latex is ubiquitous in modern society and particularly in health care.
William Halstead first used latex surgical gloves in 1890. Latex has been used
in a myriad of medical devices for decades. In the late 1980s, however, its use
skyrocketed as latex gloves were widely recommended to prevent transmission of
blood-borne pathogens, including the human immunodeficiency virus (HIV).
Billions of pairs of medical gloves are imported to the United States in
annually, often as powdered, nonsterile examination gloves.
In the 1980s and 1990s, heightened demand for latex to manufacture gloves
and other objects resulted in hundreds of new, poorly regulated latex factories
in tropical countries. The incidence of minor and serious allergic reactions to
latex began to rise rapidly among patients and health care workers (HCWs).
Latex sensitization can occur after skin or mucosal contact, after peritoneal
contact during surgery, and possibly after inhalation of aerosolized particles
with latex on their surfaces.
Pathophysiology: Latex exposure is associated with 3
The first syndrome is irritant dermatitis. It is a result of mechanical
disruption of the skin due to the rubbing of gloves and accounts for the
majority of latex-induced local skin rashes. It is not immune mediated, is not
associated with allergic complications, and is not the subject of this article.
It may be confused with Type IV hypersensitivity. Any chronic hand dermatitis
in HCWs raises the risk of nosocomial infections, including blood-borne
The second syndrome is a delayed (type IV) hypersensitivity reaction,
resulting in a typical contact dermatitis. Symptoms usually develop within
24-48 hours of cutaneous or mucous membrane exposure to latex in a sensitized
person. The primary allergens are residual accelerators and antioxidants left
from the original manufacturing process. Langerhans cells process the antigens
and present them to cutaneous T cells. Multiple objects can cause
sensitization, but the most common sources in this country are probably
examination gloves for adults and shoe soles for children. Type IV
hypersensitivity is more common in atopic individuals. The dermatitis may
predispose patients to further sensitizations or infections.