During pediatric check-ups, we often encounter such an opening remark:
Doctor, my child developed eczema shortly after birth. I’ve stopped breastfeeding and switched to extensively hydrolyzed formula milk, but it’s still not getting better. What should I do?
Doctor, my child’s eczema keeps recurring. I’ve restricted my diet to only cabbage and pork, but it’s still not improving. Can I still breastfeed?
……
When children have eczema, parents search online and see many suggestions for dietary avoidance, which easily leads them to suspect that their child’s eczema is caused by food allergies. This leads to a firm belief in dietary restrictions and a simultaneous avoidance of normal treatments
(corticosteroid therapy). However, such thoughts are all mistaken. Today, let’s discuss this topic.
Why do children develop eczema?
Eczema, also known as atopic dermatitis, is a chronic, itchy, inflammatory skin condition that is common in both children and adults and has a certain genetic predisposition.
Its occurrence and recurrence are caused by multiple factors such as epidermal barrier dysfunction, genetics, immunity, and changes in skin microbiota working together and promoting each other.
The so-called epidermal barrier refers to the cells of the epidermis layer of the human skin, which are closely and orderly arranged to form a protective barrier for the human body, just like a solid wall.
The epidermis is composed of five layers from the outside to the inside: the stratum corneum, the clear layer, the granular layer, the spinous layer, and the basal layer.
The function of the epidermal barrier is mainly in the stratum corneum (like the outermost layer of the wall). The stratum corneum is a physical barrier formed by vertically and tightly stacked anucleate keratinocytes(these cells are like the bricks in the wall), which helps people resist environmental damage (including pathogens and allergens).
Keratinocytes synthesize filaggrin, which is transformed into filaggrin breakdown products, located in the upper part of the stratum corneum, and is natural moisturizing factor, which can maintain skin hydration and water retention in the stratum corneum in low humidity environments.
In addition, the lipids in keratinocytes have a hydrophobic effect and can also limit transepidermal water loss, helping to maintain the body’s water balance.
These substances are like the cement between the bricks, making the wall more airtight and solid.
The integrity of the epidermal barrier helps maintain the stability of the structure and function of the human skin and deep tissues, keeping the body in a healthy state.
When some factors lead to the destruction of the epidermal barrier structure, resulting in increased transepidermal water loss, increased permeability, reduced hydration, and changes in lipid composition, they also make bacterial toxins, allergens, and other environmental irritants more likely to penetrate the skin, these changes ultimately cause skin inflammation and even systemic inflammation.
How is the epidermal barrier destroyed?
1. The impact of genetic factors on the epidermal barrier
As mentioned earlier, filaggrin breakdown products are the moisturizing factors of the skin, and the precursor of filaggrin, profilaggrin, is encoded by the FLG gene.
When the FLG gene undergoes loss-of-function mutations, it leads to reduced synthesis or functional defects of filaggrin, resulting in epidermal barrier dysfunction. This also partially explains the genetic predisposition to eczema.
2. The impact of immune factors on the epidermal barrier
Keratinocytes and immune cells in the skin can recognize signals of tissue damage or microbial stimulation, then release alarmins to the deep tissues.
These alarmins can activate downstream immune cells, releasing a series of cytokines, including IL-4, IL-5, IL-13, and IL31.
Some cytokines can promote the occurrence of inflammation and the generation of antigen-specific IgE (immune globulin related to allergies) molecules, and inhibit keratinocytes from synthesizing filaggrin, promote epidermal hyperplasia, thereby affecting epidermal barrier function.
Some cytokines can also activate the skin’s itch neurons, making the body overly sensitive, so that normally harmless stimuli (sweating, contact with wool) can also cause itching.
Itching leads to scratching, scratching further damages the skin, destroys the barrier, and worsens itching, which is the vicious cycle of itching and scratching.
3. Changes in skin microbiota
The skin of eczema patients often shows reduced diversity of bacterial communities and overgrowth of Staphylococcus aureus, which can produce a variety of bacterial proteins.
Some bacterial proteins can directly damage keratinocytes, some can cause inflammatory reactions in keratinocytes, and some can act as superantigens leading to excessive release of cytokines by immune cells and degranulation of mast cells.
The consequences of these events are direct and indirect damage to the epidermis and further destruction of barrier function.
It can be seen that, the recurrence of eczema is due to the interweaving and joint action of the above factors, with the core link being the dysfunction of the epidermal barrier.
Eczema patients are more likely to have positive results in food skin prick tests or positive food serum allergen-specific IgE (meaning food sensitization). The high rate of sensitization is due to the easier entry of food allergens into the skin with impaired epidermal barriers, and the inflammatory skin environment is more likely to lead to the production of IgE.
However, food sensitization does not equate to food allergy.
If eczema always occurs after consuming a certain food (especially milk, eggs, or wheat) or significantly worsens, the possibility of food allergy as a trigger increases (but it’s not certain, after all, the causes of eczema are complex).
If you suspect that a certain food has caused eczema, stop the food for 1-2 weeks and then add it back. If the rash improves after avoiding the food and recurs after re-adding, it is likely that the food has triggered eczema. It is recommended to avoid the food and regularly assess and re-add the food under the guidance of a doctor.
If avoiding food does not lead to improvement of eczema, or re-adding the food does not cause eczema to recur, both can rule out food-induced eczema. It is recommended to continue eating the food, even if skin prick or serum specific IgE tests are positive.
Studies have confirmed that if eczema patients avoid foods they can tolerate for a long time (foods that are positive for allergen tests but cause no symptoms after consumption), they may cause acute or severe allergic reactions when they come into contact with the food again. This phenomenon may be due to the body losing immune tolerance to the food after avoiding it.
Therefore, eczema patients should avoid blindly avoiding foods, and mothers who breastfeed eczema babies should also avoid widely avoiding foods, as this not only poses nutritional risks but may also lead to allergies to foods that were not originally allergenic.
In other words, normal intake of a variety of foods is not only conducive to a balanced diet but also reduces the risk of allergies. Why not do it?
After understanding the causes of eczema, it is clear that blind dietary restrictions are not advisable. Targeted treatment based on the pathogenesis of eczema is the preferred choice.
The following are recommendations for relieving eczema symptoms and reducing eczema recurrence:
1. Adequate skin hydration
Use children’s moisturizers to hydrate your baby’s skin every day, especially eczema and dry areas, with no limit on the number of times, as long as the skin is kept moisturized.
More than 100g of moisturizer is needed per week, and a small amount can be applied to the folds of young babies, such as the neck, to prevent friction rash (diaper rash).
2. Reduce environmental stimulation
Wear breathable cotton clothes close to the body, and the thickness of the clothes should be appropriate (the chest and back should be warm and sweat-free, and slightly cool hands and feet are not a concern). Environmental humidity 40-60%.
Bath management can be done every day, preferably in a tub, with water temperature 32-37℃
After bathing, gently pat dry the water with a soft towel, avoid wiping back and forth, and gently apply moisturizer from top to bottom all over the body within 3-5 minutes.
3. Standardized medication use
The first-choice treatment for eczema is topical corticosteroids, and the appropriate type should be chosen after a doctor’s assessment.
Generally speaking, those with mild conditions start with weak potency corticosteroid creams/ointments, and gradually reduce the dosage until discontinuation as symptoms improve; those with moderate to severe conditions start with moderate to strong or even super potent corticosteroid creams, and switch to lower potency formulations after quickly controlling inflammation until the skin lesion subsides.
Standardized medication can better reduce recurrences, and the rational choice of topical corticosteroids for eczema treatment is safe and will not affect children’s growth and development.
Further reading 👇: 1. Topical steroids, are you afraid? Discussing 7 misconceptions about steroid treatment 2. The correct way to use topical steroids 3. 9 things that can alleviate ‘eczema symptoms’, don’t take it lightly (recommended to collect)
After adequate skin care and anti-inflammatory treatment, the itching symptoms of eczema are usually significantly improved. If it still affects life, you can try second-generation antihistamines such as cetirizine hydrochloride.
For moderate to severe eczema and itching that cannot be improved by topical medications and oral drugs, biologics – dupilumab, can be considered. It directly inhibits the important inflammatory factors IL4 and IL13 in the eczema inflammation pathway, which can quickly and effectively relieve rash and itching symptoms. Further reading 👉: Eczema itching, severe skin damage? In addition to topical medications and endurance, there is also this method.
I hope that those of you troubled by eczema will gain new insights after reading this article.
Is eczema related to food allergies? Is dietary restriction necessary?
Most eczema patients with positive food allergy tests do not experience worsening of eczema after consuming these foods, which means there is no food allergy.
This phenomenon may be due to the body losing immune tolerance to the food after avoiding it.
How to properly deal with baby eczema?
(32-34℃ in summer, not exceeding 37℃ in winter), using soap-free, neutral pH mild body wash, no need for body wash if not dirty, and bath time is 5-10 minutes.
References
