Latex allergy

Three different reactions

Latex comes from the sap of the rubber tree, and reactions to rubber products fall into three groups that are often treated as a single condition of varying severity. They are not. They have different causes, different timing and very different implications.

Immediate allergy to latex protein is the one that matters most. It is driven by IgE antibodies, appears within about five to fifteen minutes of contact, and it is the only one of the three that can cause anaphylaxis.

Delayed contact dermatitis appears days after contact as an itchy, scaly rash, sometimes with small blisters. Here is the part that surprises people: it is usually not caused by latex protein at all, but by the chemicals added during manufacture — accelerators and antioxidants such as thiurams, carbamates and mercaptobenzothiazole. True delayed allergy to latex itself is much less common than the immediate kind.

Irritant reactions are not allergy at all. Friction, sweating inside a glove, occlusion and residues of soap or detergent trapped against the skin produce sore, dry, cracked hands with no immune involvement whatever. This is the commonest of the three in people who wear gloves for work.

The distinction is practical rather than academic. Sore hands from wearing gloves all day are most likely irritant, and that does not mean a risk of a serious reaction. A rash appearing two days later points to the manufacturing chemicals, which means a different glove may solve it. Hives appearing within minutes of putting a glove on is the one to take seriously.

Immediate latex allergy

Symptoms begin where the contact happened and can spread. Hives at the point of contact, itching and swelling are typical, along with sneezing, a running nose, itchy eyes, coughing and wheeze where the protein has been inhaled.

Anaphylaxis is the serious outcome, and it is most likely where latex meets a mucous membrane or gets inside the body — during surgery, dental treatment, an internal examination, or catheterisation — rather than from handling a rubber band. The signs are swelling of the lips, tongue or throat, difficulty breathing, a sudden fall in blood pressure, faintness or collapse. The pulse typically rises rather than falls.

Anaphylaxis needs adrenaline by intramuscular injection into the outer thigh, given early, and an ambulance on 999 even if the adrenaline appears to have worked.

Who is at higher risk

Anyone repeatedly exposed to latex can become sensitised, though most people never do. The groups where it is more common are:

People who wear gloves constantly for work — healthcare and dental staff, cleaners, hairdressers, food handlers — and those working in rubber manufacture.

People who have had many operations or procedures, and in particular children with spina bifida or congenital abnormalities of the urinary tract, where repeated catheterisation means repeated contact with latex against mucous membranes from an early age. Rates in that group are strikingly high, and latex-free care is standard practice for them for exactly that reason.

Anyone who has had an unexplained anaphylactic reaction during an anaesthetic, where latex is one of the possibilities that needs ruling out.

People who are already atopic, or who have certain food allergies.

The powder problem, and why older advice reads oddly

Latex gloves used to be dusted inside with cornstarch powder to make them easier to put on. The powder picked up latex proteins from the glove and carried them into the air when the gloves were snapped on or off, turning a contact allergen into an airborne one. That is why latex used to cause asthma symptoms in people who had not touched anything, and it was made worse in the 1980s when a surge in glove demand led to manufacturing shortcuts that left more allergenic protein in the product.

Powdered natural rubber gloves have since been withdrawn from healthcare use, and non-powdered gloves and nitrile or polyurethane alternatives are standard. This matters when reading anything written before that change: advice built around powdered gloves, and descriptions of latex as an airborne hazard in hospitals, describe a situation that no longer applies in the same way.

Where latex turns up

In healthcare: gloves, catheters, tourniquets, injection ports, drainage tubing, dental dams, blood pressure cuffs and parts of anaesthetic equipment.

Everywhere else: balloons, condoms and diaphragms, elastic in clothing and waistbands, rubber bands, erasers, swimming caps and goggles, some sports equipment, the grips on tools and racquets, rubber-backed mats and some adhesives.

Balloons and condoms are the two that cause most trouble outside work, the first because they are handled and inflated by mouth, the second because of mucosal contact. Non-latex condoms are widely available, and that is a conversation worth having rather than discovering the problem at an awkward moment.

The food cross-reaction

Some proteins in latex resemble proteins in certain foods closely enough for the same antibodies to recognise both. The foods involved are chiefly banana, avocado, chestnut and kiwi, with tomato, potato and papaya also described.

The important qualification is one that older advice gets wrong by telling people with latex allergy to avoid these foods as a matter of course. That is not the recommendation. Cross-reactivity on a test does not mean a reaction on eating, and routinely cutting out a list of foods on the strength of a latex diagnosis is the same mistake as building an exclusion diet from a positive test with no supporting history. What matters is whether a particular food actually causes symptoms, and that is a question for assessment rather than assumption — see allergy tests and what the results mean, and food allergies if a reaction has occurred.

Medical and dental care

This is the practical heart of it, because it is where the risk concentrates and where something can actually be arranged in advance.

A confirmed latex allergy should be recorded in medical and dental notes and mentioned at every appointment, before any procedure, and to the anaesthetist before surgery. Services are expected to be able to provide latex-safe care: non-latex gloves, latex-free injection ports, and latex items covered or substituted where they would touch mucous membranes or broken skin.

Where a latex-free theatre is not available, patients with latex allergy are scheduled first in the day, before latex has been in use in the room. A medical alert bracelet is worth considering, and whether to carry an adrenaline auto-injector is a question for the allergy clinic rather than a general rule — it depends on what kind of reaction has occurred and what exposure is likely.

Getting it confirmed

Diagnosis rests mostly on the history: what happened, how quickly, and in what circumstances. Reactions during surgery or dental treatment, wheeze or a rash from blowing up balloons, and a pattern of symptoms that tracks glove use are all telling.

Testing depends on which reaction is suspected. Skin prick testing or a blood test for specific IgE is used for immediate allergy; patch testing is the test for the delayed, chemical-driven kind, since the mechanism is different and the immediate tests will not show it. Getting the right test done depends on describing the timing accurately, which is the other reason the three-way distinction is worth understanding.

Living with it

Sensitisation is lifelong and there is no treatment that removes it, so management is avoidance plus knowing what to do if exposure happens. In practice that is manageable: alternatives exist for almost everything, and the single most valuable habit is simply telling people — clinicians, dentists, anyone about to carry out a procedure — before rather than after.

The general picture of how allergy works covers the mechanisms in more detail.