Contact dermatitis is a type of eczema that occurs when the skin reacts to direct contact with certain substances. It manifests as an itchy, red, and inflamed rash triggered by irritants or allergens in everyday items such as soaps, cleaning products, cosmetics, and metals.
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From May to September in Hong Kong, the average monthly rainfall totals up to 250mm , leading to highly humid environments. The high humidity and warm temperatures in Hong Kong can worsen contact dermatitis symptoms, making flare-ups more uncomfortable and potentially prolonging recovery. That’s why it’s important to identify triggers early, manage symptoms effectively, and take preventive measures to protect the skin from further irritation.
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What is Contact Dermatitis?
Contact dermatitis is a type of eczema that occurs when the skin reacts to a substance, leading to inflammation and irritation. These triggering substances can be categorized as irritants or allergens.
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Eczema, as a broader term, refers to various conditions that cause dry, itchy, and inflamed skin. Contact dermatitis is unique because it is triggered by external exposure or an internal immune reaction. The severity of the reaction depends on skin sensitivity, duration of exposure, and the strength of the irritant or allergen. One of the key characteristics of contact dermatitis is that it improves when the triggering substance is identified and avoided. While some cases resolve quickly, persistent exposure can lead to chronic irritation, discomfort, and recurrent flare-ups.
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The Two Types of Contact Dermatitis
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Irritant Contact Dermatitis
Irritant contact dermatitisis the most common form of contact dermatitis, affecting people who frequently handle harsh chemicals, soaps, or solvents. The condition arises when the outer layer of the skin (epidermis) becomes damaged, leading to dryness, irritation, and inflammation.
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A well-known example is housewife’s dermatitis, which develops from repeated hand washing and prolonged exposure to cleaning agents. Alkaline or acidic substances strip away the skin’s natural protective barrier, making it vulnerable to irritation. Even minor cuts or cracks in the skin can worsen symptoms, leading to redness, peeling, and discomfort.
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Unlike allergic contact dermatitis, which involves an immune response, irritant dermatitis is caused by direct damage to the skin. The dermatitis reaction may not be immediately seen, as symptoms can develop several days after exposure.
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Allergic Contact Dermatitis
Allergic contact dermatitis involves an immune system reaction rather than relying on the substance's exposure to the skin's outer layer (epidermis). It occurs when the body identifies a substance as harmful and triggers an allergic response. This type of reaction typically affects individuals with a genetic predisposition to allergies.
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Common allergens include:
● Metals like nickel and bronze found in jewelry, belt buckles, and watches.
● Fragrances and preservatives in skincare products, perfumes, and shampoos.
● Hair dye and latex gloves frequently encountered in hairdressing and healthcare professions.
●Industrial chemicals found in the construction and dyeing industries.
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Unlike irritant contact dermatitis, allergic reactions do not always occur immediately. The body may sensitize over time, meaning repeated exposure increases the risk of developing a skin reaction.
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The Symptoms of Contact Dermatitis
The main symptom of contact dermatitis is a rash, which can vary in appearance based on the severity of the reaction. Depending on an individual's natural skin tone, the affected area often appears red, purple, or darker than the surrounding skin. The rash may be swollen, raised, or bumpy, with a cluster of tiny blisters in severe cases.
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Other symptoms include:
●Oozing fluid or pus, particularly if the rash becomes infected.
●Itching and burning, which can be intense and uncomfortable.
●Dry, cracked, or peeling skin, especially in cases of prolonged irritation.
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It is always advised not to scratch the rash, which can break the skin barrier. Once the skin barrier is destroyed, the risk of infection increases and the healing period is extended. While contact dermatitis symptoms may look severe, the condition is not contagious. This is because everyone is unique in what they are allergic to, and not everyone will react the same way to the allergen.
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Where Will I Experience Symptoms of Dermatitis on My Body?
The location of the contact dermatitis symptoms depends on where the skin was exposed. The face and neck are common areas, particularly the cheeks, eyelids, and lips, as these areas are frequently in contact with cosmetic products and skincare ingredients. The hands, fingers, and arms are common sites of irritation, as they are the first contact points for cleaning agents, detergents, and chemicals. Individuals in construction, hairdressing, and healthcare professions are especially prone to occupational exposure, so it’s advised for employers to provide adequate protective equipment for employees in the workplace, like gloves and facemasks.
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Treatments for Contact Dermatitis
Treatment for contact dermatitis typically focuses on two main approaches: avoiding the triggering substance and managing symptoms with medication.
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Identifying and eliminating exposure to irritants or allergens is the most effective way to prevent flare-ups and allow the skin to heal. This may involve switching to fragrance-free and hypoallergenic skincare products, wearing protective gloves when handling cleaning agents or chemicals, and replacing nickel jewelry with hypoallergenic alternatives. For individuals frequently exposed to irritants at work, using barrier creams can help protect the skin from prolonged exposure to harsh substances.
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If symptoms persist or become severe, medical treatments can help reduce itching, inflammation, and discomfort. Over-the-counter anti-itch creams containing hydrocortisone can provide relief, while topical or oral antihistamines can help counter allergic reactions. In more severe cases, corticosteroid creams or oral prednisone may be prescribed to reduce inflammation and speed up healing.
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With proper contact dermatitis treatment, symptoms can typically clear up within a few weeks, though the itching may subside before the rash entirely disappears. In mild cases, avoiding the triggering substance can lead to a quick recovery within a few days.
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Stronger Skin, Better Protection
Contact dermatitis can be frustrating, especially in Hong Kong’s hot and humid climates. It is a manageable condition that requires understanding the difference between irritant and allergic contact dermatitis. To have control over contact dermatitis, identifying triggers early and making simple adjustments, such as choosing gentler products and protecting the skin from exposure, can significantly reduce symptoms and prevent future outbreaks.
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Remarks:
1. Source : Climate in Hong Kong. (2024) Climates to Travel. https://www.climatestotravel.com/climate/hong-kong#google_vignette
2. Source : Contact dermatitis. (2023) NHS. https://www.nhs.uk/conditions/contact-dermatitis/
3. Source : Health Channel Understand Occupational dermatitis. (2021) https://www.oshc.org.hk/oshc_data/files/greencross/2021/%E7%9A%AE%E8%86%9A%E7%82%8E.pdf
4. Source : ccupational Disease Case Records - Contact Dermatitis. (2003) https://www.labour.gov.hk/tc/public/oh/Contact_Dermatitis_TC.pdf
