Allergic reactions to aspirin
and other pain killers
Aspirin has long been used to reduce pain from inflammation (redness and swelling) and injury, aswell as fever. Although it was originally isolated from plants in the early 1800's, aspirin is now madesynthetically. A number of similar synthetic non-steroidal anti-inflammatory drugs (NSAIDS) have also
been introduced.
How do aspirin and NSAIDS work?
Aspirin and NSAIDS work by inhibiting production of compounds in the body known as prostaglandins,which are involved in tissue inflammation, pain and fever. Aspirin also inhibits the activity of bloodelements known as platelets (which help clotting). Therefore aspirin also thins the blood, thusreducing the risk of heart attacks and strokes. There is also recent evidence that aspirin may evenreduce the risk of bowel cancer.
All drugs are potential poisons; aspirin is no exception
Common side effects of aspirin include bruising and stomach upset (or even ulcers or bleeding fromthe bowel), at high dose. Very high doses may cause confusion or ringing in the ears (tinnitus). Itshould also be avoided in children, as aspirin can trigger a condition as Reye's syndrome, wheresevere liver inflammation and damage occurs.
Aspirin and allergy
Mild to severe allergic reactions to aspirin may occur in some people. Symptoms include flushing,itchy rashes, blocked and runny noses and severe difficulty in breathing or asthma, usually within anhour of taking a tablet. If you have hives (urticaria), nose / sinus disease or asthma this can increasethe likelihood of aspirin allergy to approximately 10-30% compared to 1% in people without theseconditions.
The presence of aspirin is not always obvious
Aspirin is present in many over the counter painkillers and:
? medications for pain from headache, periods, sinus
? cold & flu tablets
? Alka-Seltzer
? Inflammatory Bowel Disease Drugs – Mesalazine, Salazopyrin
? Complementary Alternative Medicines – Willow Tree Bark extract, some herbal arthritis pills
? Topical salicylates such as teething gels (Bonjela, Oral-sed Gel)
If you are sensitive to aspirin, you will need to carefully read medicine labels and be cautious abouttaking any pain killer without talking to your doctor or pharmacist first.
There are many brands of NSAIDS
Because there are so many brand names of the same medication, and so many types of medicationsavailable, accidental exposure to aspirin or NSAIDS may occur. It is therefore important to tell yourpharmacist or health professional about your sensitivity to these medicines.
Testing for drug sensitivity
The reason why allergic reactions to aspirin and related pain-killers occur is uncertain. There is noreliable blood or skin allergy test which has been proven to be useful for confirming or excludingsensitivity to these medicines. The only way to do so is a graded open challenge under strict medicalsupervision. Challenge testing is not always necessary, but may be advised in some circumstances: toprove that sensitivity exists, or to prove the safety of an unrelated medicine, so that you have anotherdrug from which to choose if you need to use a pain killer.
What is aspirin desensitisation?
This is useful in some people with aspirin allergy, nasal polyps and asthma. It can be used to:
? improve asthma control
• reduce the severity of sinusitis/nasal polyposis
• reduce the rate at which polyps regrow
• enable people to use aspirin or similar medication for treatment of heart disease or arthritis.
Side effects can include:
• Stomach Irritation – ulceration and bleeding at high doses
• Easy bruising – common
• Tinnitus (ringing in the ears – rare).
The decision to undertake aspirin desensitisation should be made in consultation with an allergyspecialist.
Management of aspirin / NSAID sensitivity
Ongoing hivesIf you have on-going hives or urticaria, you should avoid aspirin and NSAIDS unless you know thatyou can tolerate them without a problem. If you are already taking regular aspirin (for example, to thin
the blood), or a regular arthritis tablet for treatment of pain, then you do not need to stop this medicineunless your hives clearly get much worse after taking a tablet.
Acute hives/severe allergic reactions after a pain-killer
Most people with aspirin/NSAID allergy are sensitive to only one drug. Unfortunately, up to 1 in 5 mayhave unpredictable cross-reactive allergic responses to similar medicines.
Under these circumstances,an open challenge with a completely different drug can be considered if you need to take a pain killerfor treatment of pain.
Aspirin sensitive people with asthma, nasal polyps and sinusitis/rhinitis
Leukotriene "blockers"/antagonists such as Singulair (montelukast) or aspirin desensitisation (seeabove) are useful treatment options.
Tolerability of new medications
A number of new medications have been introduced in the last few years such as Celebrex and Vioxx.Whilst they cause less stomach irritation than aspirin and traditional NSAIDS, around 5 - 20% ofpeople with aspirin allergy may have allergic reactions to these as well.
Dietary salicylates in aspirin-sensitive patients
Occasionally people who are allergic to aspirin and have asthma, nasal polyps and sinusitis/rhinitiswilll suffer symptoms if they eat foods that have high levels of natural salicylates in some food. Thisaffects the occasional person rather than the majority, so low salicylate diets are not considered aroutine part of management.