Contact Allergy

Do you suffer from skin irritations such as itchiness, rashes and hives, but have no idea what is causing them after your skin comes in contact with certain substances?

Unbeknownst to many, the underlying causes of allergies differ from individual to individual. The three most common causes of skin allergies are contact allergy, food allergy and drug allergy.

What is Contact Allergy?

Contact allergy, also known as contact dermatitis, is what happens when your skin comes into contact with substances that can cause a rash or irritation. There are 2 types of contact dermatitis - irritant contact dermatitis and allergic contact dermatitis. Irritant contact dermatitis occurs when skin comes into contact with a harmful chemical that can erode the natural defences of the skin. Allergic contact dermatitis occurs when a substance triggers your immune system, causing an allergic reaction. This normally occurs with an itchy rash that may become swollen or blister over time.

If left untreated, contact dermatitis can lead to itchy and dry patches on the skin that do not heal for several months. This often happens due to repeated and prolonged contact with a particular allergen.

Common causes of Contact Allergy in Singapore?

Substances that cause contact dermatitis in individuals vary greatly. Some may experience an allergic reaction after immediate exposure, while others develop rashes after repeated contact with a particular substance.
Irritant contact dermatitis can be work related as well and is often seen in healthcare workers and cleaners who use latex gloves, hand sanitizers and became more prevalent in the population during the Covid-19 pandemic.

These are the commonest contact allergens on adults in Singapore:

• Metals like nickel and chromate that can be found in watches, belt buckles, costume jewellery.
• Fragrance in perfume, cosmetics
• Colophony in bandages and adhesive materials.
• Para-phenylinediamine(PPD) found in hair dye
• Topical medicament such as antibiotic creams and lotions
• Rubber and latex gloves
• Chemicals and solvents including bleach and detergent

Common causes of of Contact Allergy in Children and babies include

• Nickel found in fluorescent paint, buttons in shorts/ skirts, shiny toys
• Preservatives like methylisothiazolinone that can be found in wet wipes
• Cocamidopropyl betaine, tear free ingredient in baby soaps and shampoo

What are the symptoms?

You may be suffering from contact allergy if you often experience the following symptoms:

• Itchy rashes and/or hives
• Dark or leathery patches on the skin (hyperpigmentation)
• Bumps and blisters that sometimes ooze
• Dry, cracked, flaky and scaly skin
• Swelling, burning and tenderness
• Redness and inflammation of the skin

Is Contact Allergy painful?

Contact allergies can be uncomfortable, painful, and itchy, not to mention disruptive to everyday activities. They can cause your skin to become red and inflamed. Rashes can also lead to scarring and skin discolouration.

Who is at risk of Contact Allergy in Singapore?

Anyone can develop contact allergies at any age. However, there are certain risk factors such as age, genetics and medical history. Those who work in certain professions in Singapore, where they are continuously exposed to chemicals and substances that often cause contact dermatitis, are also more at risk. In Singapore, one of the most common contact allergies in adults and children is nickel.

How is it diagnosed?

Contact allergies are often diagnosed through skin patch testing, which also determines the source of your allergy.

Skin patch testing is a safe and simple procedure. It consists of applying patches that hold a tiny amount of suspected contact allergens onto the skin, then sealing it with hypoallergenic tape. Approximately 20 to 30 substances that typically cause contact dermatitis such as fragrances, metals, resins and preservatives can be simultaneously tested during this procedure.

After 48 hours of wearing the patches, your dermatologist will check to see if the skin has been irritated. If so, this means you have tested positive for one, or more, of the substances, which indicates contact allergy.

What are the treatment options for Contact Allergy in Singapore?

There is no cure for contact allergies. The standard treatment is to first identify the contact allergen (or allergens), and then avoid it altogether.

Once the underlying cause of your contact allergy has been determined, your dermatologist may prescribe anti-inflammatory creams to treat skin irritations and/or antihistamines to prevent further allergic reactions.