Latex Allergy

Definition

A latex allergy is a hypersensitivity reaction to natural rubber latex found in a variety of household, work-related and medical items. Latex is a commonly occurring substance in modern life and particularly in the health care industry. Exposure to latex is therefore often unavoidable. While it does not cause any irritation nor pose a threat to most people, some individuals have varying degrees of hypersensitivity to latex. It can lead to minor symptoms like itching of the skin or can even progress to widespread and severe systemic manifestations which may be life threatening.

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Incidence

Up to 1 in 20 people in the general population in the United States have a latex allergy. The incidence may be as high as 17% among health care workers and about 10% among workers in the rubber industry. A latex allergy is more common among atopic individuals – people who have an allergic disposition and experience related conditions like atopic dermatitis. There is no difference in the incidence between males and females but it tends to be more common among children and young adults.

Pathophysiology

Allergies arise when a person who is hypersensitive has an immune-mediated reaction when exposed to specific substances (allergens). Not every case of latex allergy is actually due to an allergic reaction. In fact often it is due to the mechanical irritation of the item containing latex leading to irritant contact dermatitis. The fact that latex is within the substance does not really matter as the rubbing and moisture (usually perspiration) is the source of irritation.

With a latex allergy, the person must have had prior exposure to latex. The immune system becomes hypersensitive to an otherwise harmless substance. Upon contact, histamine and other chemicals are released in large quantities thereby eliciting the symptoms seen with a latex allergy. The allergic reactions to latex occurs as a result of :

  • Type IV hypersensitivity reaction which causes a localized response that is delayed.
  • Type I hypersensitivity reaction which leads to a systemic response that is immediate.

Localized  Reaction

This often the more common allergic manifestation to latex. The area that comes into contact with the latex is where the main symptoms are seen and remains localized at this site. It is a type IV hypersensitivity reaction mediated by T-cells which come into contact with the antigen, in this case latex. This type of response is a typical allergic contact dermatitis and the symptoms start between 24 to 48 hours after exposure. It is therefore known as a delayed hypersensitivity reaction.

Systemic Reaction

Type I hypersensitivity reactions to latex can be very serious. Reactions occur within 30 to 60 minutes after exposure to latex, which may be due to direct skin contact, inhalation or inoculation into the skin or bloodstream. Therefore it is known as an immediate hypersensitivity reaction. It is mediated by specific IgE (immunoglobulin E) antibodies that are already present in the body. The symptoms can vary from urticaria in a specific area of the body or even throughout the body. Sometimes it can lead to anaphylaxis in rare instances and emergency medical intervention is necessary to prevent death.

Symptoms

The symptoms of a latex allergy can vary depending on whether it is a type I or type IV hypersensitivity reaction. It also depends on where the contact with latex is made – skin, eyes, nose, mouth, vagina or penis. The variation in location is dependent on the type of latex-containing item that a person comes in contact with, such as latex gloves, condoms and so on. The symptoms of a latex allergy anywhere on the skin, eyes, within the nose, inside the mouth, vagina or penis may therefore include :

  • Intense itching (pruritis)
  • Swelling (edema)
  • Reddening

These are generalized features of inflammation which is triggered by different immune cells and chemical mediators. More specifically, there may be :

  • Red, swollen or thickened patches
  • Small blisters (vesicles)
  • Urticaria with angioedema
  • Conjunctivitis with excessive tearing
  • Rhinitis (runny nose)
  • Abdominal cramping
  • Nausea, vomiting and diarrhea

Warning Signs

Due to the possibility of a type I hypersensitivity reaction, the following symptoms must be taken very seriously and immediate medical attention should be sought.

  • Difficulty breathing – shortness of breath, gasping.
  • Abnormal breathing sounds – stridor, wheezing.
  • Lightheadedness and fainting.
  • Lump in the throat feeling with hoarse voice.
  • Paleness with cold and clammy skin.
  • Hypotension – low blood pressure.

Causes

The cause of a latex allergy is exposure to substances or items containing latex. The response is due to a hypersensitive immune system reacting to the presence of latex on the skin or mucous membrane in sensitized people. Latex is the milky fluid from rubber trees. It can be mixed with other substance to form rubber. It is a the proteins within latex that is the most allergenic component of the substance.

In modern life, latex is present in a wide variety of items and the source is therefore not always obvious. It is therefore important to consider the items containing latex that may be encountered in the home, at work or in health care facilities. Latex is widely used because it is durable, elastic and fairly inexpensive. Even though it can trigger allergic reactions in some people, it is non-toxic.

Medical

  • Blood pressure cuffs
  • Catheters
  • Dental dams
  • Electrode pads
  • Goggles
  • IV tubing ports
  • Stethoscopes
  • Surgical gloves
  • Syringe plungers
  • Tourniquets

Household

  • Balloons
  • Baby bottle nipples (teats)
  • Barrier contraceptives – condoms and diaphragms
  • Clothing elastic
  • Computer mouse pads
  • Carpets
  • Erasers
  • Garden and kitchen gloves
  • Rubber bands
  • Rubber grips
  • Soles of shoes
  • Vehicle tires

Diagnosis

A latex allergy is not always obvious as some patients may have mild symptoms and may not associate it with a latex allergy. Furthermore symptoms of delayed hypersensitivity reactions (type IV) may only arise a day or two after exposure and once again the association may not be made with a latex allergy. Latex is so widely used that many people are unaware of the substance in a specific item. Lastly, the symptoms of contact dermatitis is not specific for a particular substance. Therefore further testing is often necessary to confirm the diagnosis.

  • Blood tests  :
    – IgE levels
    – Radioimmunoassay test (RAST)
    – Enzyme linked immunosorbent assay (ELISA)
  • Skin tests :
    – Skin patch test
    – Skin prick test

Diagnostic investigations like skin prick tests need to be done with caution in patients with immediate (type I) hypersensitivity reactions.

Treatment

In mild cases of contact dermatitis caused by latex, no specific treatment may be necessary. The symptoms may subside within a few days with just supportive measures like an emollient. Patients need to be made aware of their latex allergy and advised to avoid latex as far as possible. In more severe cases of contact dermatitis, topical steroids may be used to reduce the inflammation and oral antihistamines are useful for symptomatic relief.

However, in the event of type I hypersensitivity reactions. emergency medical treatment is necessary. Patients need to be rushed into the emergency room. The patient needs to be stabilized using equipment that does not contain latex. Airway, breathing and circulation (ABC) must be assessed and the necessary measures taken such as oxygen therapy. Epinephrine (adrenalin) may be needed in the event of anaphylaxis, H1 antihistamines and corticosteroids may also be administered.

References :

http://emedicine.medscape.com/article/756632-overview

http://www.aafp.org/afp/1998/0101/p93.html

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