49. Latex Allergy Flashcards
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?
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%.
What types of allergy to latex do you know?
- Contact dermatitis
Type IV delayed hypersensitivity reaction to the
chemical accelerators, anti-oxidants and stabilisers
used in the manufacturing process
T-cell mediated - Anaphylaxis
Type I immediate hypersensitivity reaction to latex
proteins in previously sensitised patients
IgE mediated
How do you test for it?
Testing takes place 4–6 weeks after the reaction.
- 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.
- 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
How would you manage this case?
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:.
- Latex-free
- May be modified to be used.
- 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.
Pre-medication is controversial,
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.
Latex anaphylaxis:
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