Can allergies develop when one is already an adult?

A person may have been allergic to a substance their whole life, but only develop symptoms in adulthood if they were not exposed to the allergen when they were younger. — AFP

Most young children with allergies tend to outgrow their symptoms, developing a tolerance to the allergen after their teenage years.

However, the fact is that allergies can develop at any time during one’s life.

There is also the possibility of an allergy returning in your 20s, 30s or 40s, if your immune system is impaired from lifestyle factors, stress or medical illness.

Changes in your environment, like moving from a cold climate to a warm and humid one, or keeping a new pet, can also retrigger allergies.

Allergies can also develop later in life if you’ve had very minimal exposure to the allergen in childhood.

This is the case if you do not develop allergic symptoms until you are exposed to a higher concentration of the allergen later in life.

It is also possible to become allergic to something you had no allergy to before.

Here are some common questions patients tend to ask about allergies:

How would someone know? What tests can be done?

Some people are advised to keep an allergy diary and detail the food, environment and possible triggers they might have come into contact with.

However, this approach is still an educated guess at the end of the day.

The alternative is to either perform an IgE (immunoglobulin E) blood test or a skin prick test for allergies.

Is there a gold standard for allergy testing?

The gold standard for food allergy testing is an oral food challenge.

However, this must be done where emergency treatment and medical staff are immediately available and on standby to address any possible life-threatening reactions.

This is as the test involves slowly eating increasing amounts of a food to see if an allergic reaction is triggered.

A safer alternative is an IgE blood test.

The gold standard for environmentally-triggered allergies is a skin prick test.

This can only be performed if one has not taken any medications that interfere with the immune system (e.g. antihistamines, steroids, immunomodulators) for at least five to seven days prior to testing.

Again, an acceptable alternative without these restrictions is an IgE blood test.

Has there been an increase in the number of people suffering from allergies over the years?

Allergies are on the increase worldwide, but movement restrictions during the Covid-19 pandemic have seen an increasing number of people working from home.

Allergies can result in symptoms like a runny nose, rashes, tearing, and even diarrhoea, so it’s best to confirm the source with tests like the skin prick test. — Positive Parenting

This means that they are being exposed to their home environment on a prolonged basis.

There may be more dust at home, animals (pets or pests), or pollen from their garden, causing them to experience more symptoms.

Furthermore, the pandemic has seen more people order food delivery, which translates into not knowing what goes into their food and being unable to control the ingredients.

New food exposures could lead to previously unknown food intolerances flaring up.

What is anaphylaxis and can someone check for this in advance in both adults and children?

Anaphylaxis is a serious allergic reaction that is rapid in onset and potentially fatal.

It typically causes more than one of the following symptoms:

• Itchy rash
• Throat or tongue swelling
• Shortness of breath
• Vomiting
• Lightheadedness, and
• Low blood pressure.

These symptoms typically develop over minutes to hours.

Anaphylaxis is a medical emergency.

If you have an adrenaline autoinjector, you can use it immediately.

If not, you should head to the nearest Accident and Emergency department immediately.

Anaphylaxis is not something you can readily test for.

However, having an idea of what you are allergic to through skin prick testing or IgE blood tests can give you a very good indicator of what to avoid.

Highlighted allergens can potentially trigger an anaphylactic reaction.

What are the possible allergic reactions to Covid-19 vaccines and self-test kits?

Self-test kits are safe because there is no external allergen interaction with the body.

Previously, Covid-19 vaccines were not permitted for people with a history of anaphylaxis.

Recently however, after numerous robust studies, these vaccines have been considered safe for everyone EXCEPT those who may have an allergic reaction to the first dose.

This allergic reaction usually occurs in the first 30 minutes of the post-vaccination observation period, and can be picked up by the vaccination site medical team on duty.

ALSO READ: Are you using the self-testing Covid-19 kits correctly?

How does one manage allergies? Are allergies treatable? What are the treatments available?

Allergies can be managed through several approaches, such as allergen avoidance, symptomatic treatment and long-term sublingual immunotherapy that can potentially “cure” the allergy.

Allergen avoidance involves avoiding foods one may be allergic to, modifying one’s environment to prevent a buildup of environmental allergens such as dust mites, and/or reducing exposure to pets that may trigger an allergic reaction.

Symptomatic treatments include antihistamines, nasal decongestants, intranasal steroids and steroidal creams for rashes.

However, the more exciting development in allergy treatment is sublingual immunotherapy (SLIT).

SLIT involves “priming” the body to stop reacting to the exact cause of the allergy.

A mix of low-dose allergens are put into a spray, which is taken once a day under the tongue for three to five years.

Most patients see an improvement after six months and the best effects are usually seen after four years.

SLIT is currently only available and useful for inhaled allergens.

Studies have shown an improvement in symptoms, reduced reliance on medications and lasting effects, with some people still benefiting from it many years after treatment has stopped.

Overall, SLIT is a safe and effective treatment with no life-threatening reactions reported in over 4,500 patients treated.

What are common allergies suffered by men versus women, and the differences?

Studies have shown that post-pubertal females are at higher risk of allergies such as sensitive nose, skin, eyes and airways, as well as food sensitivities and asthma, when compared to men.

However, prepubescent males are found to have more allergies in comparison with females.

Gender differences in immune responses are complex and differ with age, and interplay on multiple levels with the immune system.

Despite these differences, what is important is that the earlier you act on these allergies, the sooner you can return to a better quality of life with improvement of your symptoms.

Dr Julian Hong is a general practitioner (GP) in Singapore. For more information, email [e-mail]. The information provided is for educational and communication purposes only, and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this article. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.