Latex allergy

What is latex?

Allergy to latex is an increasing occupational concern as more people report allergic reactions due to contact with latex products.

Latex is the milky sap obtained by tapping the rubber tree (Hevea brasiliensis). The raw material is mixed with a preservative, such as ammonia, then concentrated and shipped as a latex concentrate to make products such as disposal gloves. This milky fluid contains variable amounts of proteins that can be absorbed through the skin or inhaled and can cause allergic reactions in susceptible workers. More than 50 different proteins have been implicated in the allergic response, with up to a total of 240 different proteins found in latex.

Who is at risk?

Health care providers as well as patients have a risk of exposure to latex because there are many medical products containing latex. Latex gloves are the main source of exposure for health care providers. Concerns about AIDS and Hepatitis B and C exposures have given rise to the widespread practice of universal precautions to ensure that there is no risk of exposure to potentially infected blood and body fluid. This has meant an increased use of latex gloves and, as a consequence, an increased level of exposure to latex for health care workers.

But health care providers are not the only occupation to be exposed to latex. Other workers who are also at risk include the police and emergency medical personnel, food handlers who work in cafeterias and fast-food restaurants, sanitation workers, and workers in the latex manufacturing industry and latex toy manufacturing plants.

Sources of exposure

People who are sensitive to latex may have an allergic reaction if they come into contact with latex products, such as balloons, rubber bands, industrial gloves, rubber boots, shoes, condoms, contraceptive sponges, adhesive tape, elastic bandages, tourniquets and bulb syringes.

Many fruits and foods have similar proteins to latex and can also cause allergic reactions. These foods include banana, avocado, chestnut, passionfruit, kiwi fruit, potatoes, tomatoes, figs, apples, celery, melons, pineapples, milk, papaya, grapes and pitted fruit.

Routes of exposure

There are various routes of exposure to latex:

• Skin
  Skin exposure can occur when handling latex products, for example, medical devices such as medical gloves, tourniquets and electrocardiogram electrodes, adhesive tapes, condom catheters and ileostomy bags.
  
  
• Mucous membranes
  Latex proteins contacting mucous membranes of the mouth, vagina, urethra or rectum can lead to severe reactions. This contact might happen during physical examinations.
  
  
• Inhalation
  Cornstarch powder is applied to latex gloves during the manufacturing process to give the gloves a smooth feel and make them non-sticky. However, latex protein can adhere to the surface of the cornstarch particles. When the person removes the glove, the cornstarch powder is easily aerosolized and can cause asthmatic reactions if inhaled.
  
  
• Intravascular
  Exposure through intravascular administration of latex proteins can result from disposable syringe plungers, medications stored in vials with rubber stoppers and intravenous tubing with latex injection ports.

Types of reactions

There are three main types of latex sensitivity reactions:

1. Irritant contact dermatitis
   Has a gradual onset, taking days. Is caused by accelerators and chemicals used in the latex glove manufacturing.
   
   
2. Allergic contact dermatitis/Type 4 (Delayed hypersensitivity)
   Occurs 6 to 48 hours after contact. Can be caused by accelerators and chemicals.
   
   
3. Immediate hypersensitivity/Type 1-IgE mediated reaction
   Occurs within minutes and rarely lasts longer than 2 hours. It can have a sudden onset although the sufferer may have been using latex for years without problems.

Diagnosis of latex allergy

Latex allergy may be diagnosed taking into account a person's medical history, including an assessment of occupational and other risk factors and their previous reaction history including food allergies. Symptoms may become apparent after exposure, for example, following the use of a rubber condom or diaphragm, or following a pelvic examination.

Standardised extracts for skin-prick testing undertaken by experienced staff could be used to confirm an allergy to latex in persons who have a negative serology test, despite a strong positive history of sensitivity.

Preventing exposure

Prevent unnecessary exposure to latex products. If gloves must be worn regularly, then:

• Avoid inhaling the cornstarch powder lining the gloves. Choose powder free gloves or cotton gloves where possible.
  
  
• Wash hands after removal of glove to minimise powder remaining in contact with the skin.
  
  
• Clean up residual powder in the workplace with appropriate vacuum filter.
  
  
• Develop policies and procedures for reducing the risk of natural rubber latex allergies in the workplace.
  
  
• Provide resources and materials for staff about new non-latex products.
  
  
• Provide latex-free procedure trays and crash carts (emergency trolley) for treatment of individuals allergic to natural rubber.

If a person is already allergic to latex:

• Use alternative non-latex gloves or cotton glove liners (Hypoallergic latex gloves are not latex-free; they can contain considerable amounts of latex allergens. People who are allergic to latex should not use them.)
  
  
• Reduce and eliminate where possible material and substances containing latex in use at home and the workplace.
  
  
• Seek advice from a medical practitioner if needed.

For further information and advice contact the Workers Health Centre
02 9749 7666
admin@workershealth.com.au

Facts 0039 © Workers Health Centre, 2004