Sensitisation

There has been a steady increase in the number of reported cases of asthma and skin complaints attributed to latex during the 1990s.  There are a number of possible reasons for this including:

• increased awareness of the problem
• increased use of latex gloves, following the introduction of universal precautions
• increased use of other equipment containing latex, for example:
• catheters
• barium enema tips
• rubber bungs on medication vials.

Latex exposure can lead to a number of health problems including:

• Irritation – symptoms include: redness, soreness, dryness or cracking of the skin

in areas exposed to latex. This type of reaction is not an allergic reaction. Once the irritant agent, e.g. latex, has been identified and contact with it ceases, the symptoms will disappear and not recur.

• Type I allergic reaction – symptoms include: localised or generalised rash (urticaria or hives), inflammation of the mucous membranes in the nose (rhinitis), red and swollen eyes with discharge (conjunctivitis). asthma-like symptoms.

This is an allergic response to the extractable latex proteins and occurs almost immediately on contact.  In rare cases it may result in an extreme reaction known as anaphylactic shock, this may be life threatening but can be treated with medication.

• Type IV allergic reactions – symptoms include: dermatitis, and itching

with oozing red blisters, which are usually localised to the hands and arms.  These occur between 10-24 hours after exposure and can get worse over the next 72 hours.  This is an allergic response to the chemical additives, known as accelerators, used in the manufacturing process.

The amount of latex exposure needed to produce sensitisation is unknown.  A substance which causes sensitisation is one which is capable of causing an allergic reaction in certain people.  Once sensitisation has taken place, further exposure to the substance, even to the tiniest trace, will cause the symptoms to recur.  Increasing the exposure to latex proteins increases the risk of developing allergic symptoms.

Several types of synthetic rubber are incorrectly referred to as ‘latex’.  Equipment (e.g. gloves), which is manufactured from these synthetic rubbers may also cause an allergic response in someone sensitised to the chemicals used in the manufacturing process.

There are a number of different types of latex glove available.  Due to prolonged and close contact, all latex gloves present a particular risk of skin sensitisation, but the risk is reduced in gloves with lower levels of latex protein and process chemicals.  Powdered gloves pose an additional risk, not only to the user but also to sensitised people in the area.  The proteins in the latex glove leach into the powder, which becomes airborne when the gloves are removed.  Inhaling the powder may lead to respiratory sensitisation.