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Friday Dr Q&A with Prof Hugo – Skin Prick Test

Q&A Senior Consultant Allergy Immunology Professor Hugo for EczemaBlues

Professor Hugo van Bever is a Senior Consultant in Pediatric Allergy and Immunology at the National University Hospital, Singapore. He is an active member of the board Asia Pacific Academy of Pediatric Allergy, Respirology and Immunology. He is also my co-author for Living with Eczema: Mom Asks, Doc Answers!

This is originally a series of Friday Q&As in 2012 which has been combined into one informative post.

Eczema Baby Scratching Eyes

MarcieMom: Babies tend to scratch their eyes when tired. Also, I notice that my baby’s eyelids (where eyeliner is applied) look oily. To soothe the discomfort, I would wet a cotton pad with lukewarm boiled water and clean outwards. This is sometimes followed by moisturizing sparingly when her eyelid is dry.

How would you recommend a parent to reduce their child scratching eyes?

Prof Hugo: Keep eczema under control and apply a preventive approach.

Skin Prick Test for Kids

Marcie Mom: Today’s questions is on skin prick test, something I always recommend parents to do (in this post).
In a skin prick test, typically a few common food allergens such as egg and milk will be tested instead of all possible food that the child may eat. Why is testing a few of these food allergens sufficient to diagnose if there’s an underlying food allergy?

How often should a child get retested for food allergy? And what type of patients needs to be retested regularly?

Anti-histamines should be avoided before a skin prick test so as to avoid incorrect results (due to no reaction seen when there should be one). What else should a parent take note before bringing the child for allergy test?

Prof Hugo: Because only a few foods are involved in eczema, mainly in young children. These are: cow’s milk, egg, wheat and soy. Other foods are very seldom involved in eczema. In older children food allergy is usually not involved in eczema. Older children have mainly an allergy to house dust mites.

If the child improves there is no need to repeat skin prick test.

Skin prick test should be performed only when the child is in good health (no ongoing infection, no fever) and did not take antihistamines for at least 3 days. Antihistamines may suppress the skin prick test’s results, leading to false negative results. Skin prick test also needs an area of normal skin. In cases of severe eczema, skin prick test’s results are difficult to interpret. A blood test might be an alternative.

Topical Steroid as Treatment

MarcieMom: Many parents are worried about applying steroid cream for their child’s eczema. Recent research has shown that there is no major negative effect on the skin of children who have applied topical steroid over approximately 10 months, including no evidence of skin thinning.

What guidelines will you provide parents when applying steroids for their child (in terms of when to apply, how much to apply and which part of the skin to apply which steroid’s strength)?

Prof Hugo: Use mild steroids (for children) maximum 2 x day. Use them only on active inflammation (= “red” patches) and use them after cleaning the patches. Don’t use steroids on a dry skin or on old lesions.

Oral Steroid as Eczema Treatment

Marcie Mom: I must thank you again for helping Marcie with her eczema. I noticed that it got much better after the one-time oral steroid course you prescribed (read more in this post).

Oral steroid such as prednisolone is sometimes prescribed for children with severe eczema. Can a child only be prescribed oral steroid once? I’ve read horror stories online of how some doctors negligently keep prescribing oral steroid to the point that it no longer works for the child. How can a parent assess if the doctor is taking due care in his prescription for their child?

Prof Hugo: Oral steroids should be avoided, especially because eczema is a chronic disease, and oral steroids cannot be used chronically. Only in severe flare-ups a short course (5 to 7 days) is recommended. In some children (exceptionally) a longer treatment can be needed. However, this should be given in an EOD dose (= every other day). It is all a matter of trust in your doctor. If your child has severe eczema, needing oral steroids, I advise to see a paediatric allergist or paediatric dermatologist.

Alternative Eczema Treatments

Marcie Mom: Lots of parents are looking for a way to manage their child’s eczema (though a reminder that eczema is chronic, no miraculous cure) and may be willing to try ‘alternative treatments‘.

Many alternative treatments, including using natural remedies are marketed for eczema. Personally, I prefer sticking to moisturizing and appropriate use of steroid under doctor’s instruction. However, I understand the anxiety parents have when their child’s eczema hasn’t responded well to their doctor’s treatment.

What advice would you give a parent when deciding if they should try out a natural remedy? What is safe for them to try and what should they be wary of?

Prof HugoOnly use treatment that has been scientifically proven to be safe and effective. Many alternative treatments are available, without any study and without prove of effect: don’t try them out!

Partially Hydrolysed Milk

Marcie Mom: I have experienced switching to partially hydrolysed milk when Marcie was diagnosed with eczema.

Some research showed that giving babies partially hydrolyzed milk may reduce chance of milk allergy. I understand that it doesn’t alter the allergic profile of a child but may reduce chances of allergy as part of the milk protein is broken down. What is an allergic profile (is it part of DNA)?

Prof HugoHydrolysed milks can prevent cow’s milk allergy: that’s all. They have no effect on the long-term development of allergy. An allergic profile refers to the clinical presentation of allergy, and has nothing to do with DNA.

Food Restriction in Early Childhood

Marcie Mom: I also read that restricting a food in early childhood and introducing it later may lead to even more serious allergic reaction. What’s your understanding of how the same food allergy could progress from childhood to adulthood?

Professor Hugo: This is very individual and still confusing, because an intervention cannot be beneficial for all children, but should be tailored. More research on this is needed.

Vacuum Cleaner Selection

MarcieMom: Do you think the expensive vacuum cleaners are worth investing in? What should a parent look out for when buying a vacuum cleaner?

Prof Hugo: In case of house dust mite-allergy, a decent vacuum cleaner is recommended. However, most companies have no research data on their vacuum cleaner. Don’t spend too much money!

Sun & Haze Affect Kid’s Eczema?

MarcieMom: I read that the sun can dry the moisture on skin. Should children with eczema avoid the sun?

Prof Hugo: Active eczema (= skin inflammation) should avoid the sun.

Marcie Mom: I noticed that whenever there’s a haze (from neighbouring countries burning forests), my baby scratches a lot more. What could be in a haze and why does it irritate my baby’s skin?

Prof Hugo: Never been proven that the haze (= a type of pollution) has effect on eczema.

1 reply on “Friday Dr Q&A with Prof Hugo – Skin Prick Test”

It’s a confusing issue. There can be true allergic reactions to foods (I was not aware that so few were involved) as well as reactions that are not related to antibodies–triggers such as spices and histamines in fermented food. The more processed food you or your kid eat, the harder it is to figure out what the main causes are, if indeed the primary problem is with food.

I didn’t know, either, that antihistamines could cause problems with a skin prick test. I only wish that antihistamines actually worked to reduce itch reaction (I’ve personally found Claritin and Allegra useless, even against reactions that I assume are caused by histamines.) Perhaps Dr. Van Bever could explain why antihistamines are generally ineffective for treating eczema.

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