Discussing allergic contact dermatitis with Prof Thomas Rustemeyer

‘Allergens are small, insignificant substances but they can have a major impact on the quality of someone’s life’.

Allergic contact dermatitis is characterized by symptoms such as itching, red bumps, and blotches on the skin. It is rarely life threatening but extremely irritating. Often, a person will have used a cream for many years before suddenly developing an allergic reaction to it. The skin will suddenly become irritated and symptoms of allergic contact dermatitis will follow. The question is: why?

What is allergic contact dermatitis exactly? What causes it, and more importantly, how do you get rid of it? We consulted Prof Thomas Rustemeyer, a dermatologist/allergist and occupational dermatologist at the Amsterdam UMC, on these issues. Professor Rustemeyer has been researching allergens, substances that cause allergic reactions, for almost 25 years. He says, ‘allergens are small, insignificant substances but they can have a major impact on the quality of someone’s life’.


Prof Rustemeyer, let us get straight to the issue at hand: what is allergic contact dermatitis and how does a person develop it?

‘Allergic contact dermatitis is a developed hypersensitivity in the immune system to a particular substance. Our immune system protects us from harmful, external influences such as bacteria, viruses, and even cancer. However, if the immune system identifies a substance as an allergen even though it is not really harmful, a hypersensitivity to this substance will ensue. Allergic contact dermatitis is the result of an overactive immune system that has an exaggerated response to harmless substances. A person with this type of an immune system will experience allergic reactions when there is contact with these substances.’



Do diet and lifestyle have any influence on how the immune system reacts to allergens?

‘That is a good question as this is a very hot topic at the moment. Unfortunately we do not have enough evidence to draw any firm conclusions about this at present. There are indications that diet may be important in regulating the immune system. I like to use the analogy of a set of balance scales: If, at one end of the scale, the immune system is weak, this increases the likelihood of a bacterial infection but it might equally be the case that a fragile immune system increases the likelihood of an auto-immune response or of allergic contact dermatitis being developed. The body is more prone to infections if the immune system is compromised by such factors as the HIV virus or certain medicines. Diet can certainly have an effect in this regard as antioxidants, which are found in vegetables and fruits, stimulate healthy cell division. Fibres are also very important in maintaining bowel health, fostering healthy bacteria, and curtailing harmful bacteria. The bacterial flora largely determines how well the immune system functions. Optimum bowel health is best achieved by consuming lots of vegetables, fruits, and fibres. This has the added bonus of stimulating vitamin A production in the body. Harmful products such as cigarettes, alcohol, and too many fats should be avoided as they have a negative impact on the immune system.’

(*Vitamin A (retinol) is essential for an enhanced immune system and is good for the skin as well.)

It is clear that fruits and vegetables form an integral part of maintaining good health. Should we be purchasing organic fruits and vegetables?
‘Organic fruits and vegetables are better for the environment but there is no evidence that they are actually healthier. They tend to grow more slowly than their non-organic counterparts and produce antimicrobial proteins to ward off bacteria, yeast, and fungi. These proteins are known to cause food allergies, which are, of course, a very different phenomena to allergic contact dermatitis. Nevertheless, one could perhaps assume conventionally grown vegetables are actually better for humans than the organic variety, but this has not been scientifically proven. Personally, I would purchase organic vegetables because they are the more environmentally-friendly option but that is just a personal opinion with no scientific substantiation.’


Allergic contact dermatitis seems to be on the rise everywhere. The question is: why?

‘There are several reasons for this trend. We are facing ever-increasing exposure to allergens compared with the past. This is clear when you observe the sheer abundance of perfumes and scented products currently available on the market: figures have skyrocketed in recent years. Our lifestyles and diets have also changed over time and our stress levels are higher – these are all factors that affect how our immune system behaves. For instance, if you are stressed, your immune system is as well, making you more vulnerable to allergies.’


The number of children suffering from allergies has increased significantly as well. Expert advice varies regarding allergy prevention: some believe allergens should be avoided at all costs while others believe exposure is good as it helps strengthen the child’s immune system. Who is right?

‘If you let children play in the mud this strengthens their immune system, making them more resistant to type I allergic reactions, such as hay fever and food allergies. This has been scientifically proven. However, allergic contact dermatitis is a different type of allergy and requires a different approach. If children are repeatedly exposed to contact allergens, such as perfumes and preservatives, they are at a higher risk of developing skin allergies at a young age. Infants and young children have thin skin, making it more permeable to harmful substances. Women are also more likely to develop allergic contact dermatitis because their skin is not as thick and tough as men’s skin. In general, people who have thin skin are more likely to develop a hypersensitivity to certain substances than people who have thick skin. The truth is that half of the people who will develop a hypersensitivity at some point in their life will already have been sensitized to that substance before their 16th birthday. The worst part is that this hypersensitivity cannot be reversed: once you have had an allergic reaction to a substance, you will retain this hypersensitivity for the rest of your life. So, the message is: keep children away from strong allergens.’

Do you recommend using scrubs to keep your skin in tip-top condition?

‘No. Scrubs may make your skin feel clean and soft but they thin the skin, making it more vulnerable. Exfoliation removes dead skin cells but this is not always as desirable as people think: the dead skin cells provide a protective layer against external, harmful influences. They make the skin more resilient and ward off infection, bacteria, and UV rays. In fact, dead skin cells provide the same amount of protection as a SPF 2 or 3 sun screen. This may not seem like a lot but it makes a huge difference in the long term.’


Sunscreens are full of allergens. What is your advice in this regard?

‘SPF sunscreens may cause allergic contact dermatitis as they contain a great many chemical filters, perfumes, and preservatives. You will need to decide which is the lesser of two evils as sunscreens protect against skin cancer and premature ageing, but also contain harmful substances that can easily permeate the skin. Bear in mind that the inactive ingredients are just as easily absorbed by the skin as the chemical filters.’


We have spent the last two years working on a safe sunscreen that uses as few ingredients as possible. Our first samples have been approved and contain just seven ingredients, including natural oils to ensure the cream is readily absorbed.

‘Sunscreen and its safety have been fiercely debated over the last years, so I am very interested in learning more about your new product.’

Bear with us, Prof Rustemeyer – we hope to be able to send you a Squalan sunscreen very soon!



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