Pathophysiology
Latex exposure is associated with 3 clinical syndromes.
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 pathogens.
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.
The third, most serious, and least common syndrome is immediate (type I) hypersensitivity. It is mediated by an immunoglobulin E (IgE) response specific for latex proteins. As noted, latex proteins are highly allergenic, and they are variable between lots from different plantations, factories, and manufacturers. Cross-linking of IgE molecules on mast cell and basophil cell membranes by latex protein allergens triggers the release of histamine and other mediators of the systemic allergic cascade in sensitized individuals.
Exposure can occur following skin, mucous membrane, or visceral/peritoneal contact. It also can follow inhalation of latex-laden particles or bloodstream exposure to soluble latex proteins following intravascular access procedures. Powdered latex examination gloves have been the most frequent source of sensitization in adults, causing cutaneous and inhalational exposures. (Fortunately, their use is decreasing as many hospitals move toward powder-free, “low-allergen,” or nonlatex glove products.)
Sensitization is more common in atopic individuals. Symptoms generally begin within minutes of exposure. The spectrum of clinical manifestations includes localized or generalized urticaria, rhinitis, conjunctivitis, bronchospasm, laryngospasm, hypotension, and full-blown anaphylaxis. Type I allergy has been implicated clearly in intraoperative and intraprocedure anaphylaxis, and it can be fatal without emergent treatment.