49. Latex Allergy

Question 1

A staff nurse presents for elective surgery and claims to have a history of
possible latex allergy.
Who is at risk from developing latex allergy?

Answer 1

Patients with previous documented reactions

Those exposed to repeated medical or surgical procedures involving the use
of latex (especially bladder catheterisation)

Health-care workers

Patients with a history of atopy (may show cross-reactivity with certain
foods especially banana, chestnuts and avocado)

In spina bifida patients the prevalence may be as high as 60%.

Question 2

What types of allergy to latex do you know?

Answer 2

1. Contact dermatitis
   Type IV delayed hypersensitivity reaction to the
   chemical accelerators, anti-oxidants and stabilisers
   used in the manufacturing process
   T-cell mediated
2. Anaphylaxis
   Type I immediate hypersensitivity reaction to latex
   proteins in previously sensitised patients
   IgE mediated

Question 3

How do you test for it?

Answer 3

Testing takes place 4–6 weeks after the reaction.

1. Skin-prick testing

Involves puncturing the skin with a thin needle
through a drop of dilute antigen. The
concentration of solution is important to avoid
false negatives. There is a smaller risk of
anaphylaxis than with intra-dermal testing.

2. RAST Radioallergoabsorbent testing is less sensitive and
   more expensive than skin-prick testing, but avoids
   the risk of anaphylaxis.

As there are many different latex proteins that may be implicated in the
allergic response, a negative response to one antigen does not imply that the
patient is not latex sensitive. A strong clinical history suggestive of allergy is
important

Question 4

How would you manage this case?

Answer 4

Having already been notified in advance,
there is time to prepare the theatre
environment and equipment necessary to undertake such a case.

All theatre and ward staff should be aware of the necessary precautions to be taken.

There should be a ‘latex-free’ box of equipment available and lists of
equipment that are:.

1. Latex-free
2. May be modified to be used.
3. Must not be used at all.

The patient should be first on the list and anaesthetised in a
theatre unoccupied for at least 2 hours. The most important piece of
equipment is latex-free gloves. All other equipment should be checked with
the database in the ‘latex-free’ box.

Question 5

Pre-medication is controversial,

Answer 5

Pre-medication is controversial, but may be given to patients who are
considered to be very sensitive.
A suggested protocol for adults IV chlorpheniramine 10mg 6 hourly
would be IV ranitidine 50mg 8 hourly
IV hydrocortisone 100mg 6 hourly
Salbutamol (inh/neb) for asthmatics

This would be given for 24 hours pre-operatively and at least 12 hours
post-operatively.

Question 6

Latex anaphylaxis:

Answer 6

Reaction typically begins 30–60 minutes after the start of the
procedure (cf. anaphylactic reaction to i.v. drugs).

Management as for anaphylaxis –
think of latex-free environment as soon as is practical