Genetics vs Environment in Eczema

Surprising Lifestyle Factors That Increase and Decrease the Risk for Eczema

Share

Eczema, also known as atopic dermatitis, can affect up to 1 in 5 children and is also relatively common in adults.[1] In this skin condition, children often develop inflamed red rashes that scale and can be severely itchy. Unfortunately, many of these children have poor sleep due to constant scratching and some even develop learning disabilities and behavioral problems.

The cause of eczema is complex and consists of many factors including genetics, immune system problems, and environmental factors that can weaken the outer skin barrier.[2] It is common for parents to wonder if their child’s eczema is a result of something in the household, in their diet, or if it is genetic. Although physicians and scientific investigators do not know the exact cause, scientific knowledge is expanding regarding certain contributing factors in eczema.

 

The Role of Genetic Factors in Eczema: Father vs Mother?

Scientific evidence suggests that genetics of the parents could influence the development of eczema in children.[3,4] There is controversy regarding whether the genetics of the mother or the father has a greater influence on the eczema risk in children. While one study found that babies who had a mother with eczema had almost a 4-times higher risk for developing eczema,[5] a separate study found that there was an equal risk for the baby to develop eczema if either the mother or the father had eczema.[6] There are thousands of different genes and a complex network of immune system proteins involved in eczema, making it nearly impossible to pinpoint specific genetic variants that could lead to eczema.

Filaggrin mutations and increased eczema risk

The filaggrin gene codes for the filaggrin protein, which is crucial in the normal development of the epidermis, for strong skin barrier function, and to maintain hydration and protection. Researchers discovered that in mothers with a filaggrin gene mutation, their children had a 1.5-fold increased risk of developing eczema.[4]

Is risk for eczema linked to certain chromosomes?

Genetic testing has revealed that eczema risk may be traced to certain chromosomes, including chromosome 1,3,5,13,15, and 17.[7-9] Although the exact locations, referred to as “loci,” on the chromosomes have not been identified, it is possible that increased risk for eczema could be passed down from either the mother or the father.

 

Environmental Factors in Eczema

When a baby is first born, their immune system is not yet fully developed and various environmental factors may increase the odds for the baby to develop eczema. Some factors can even influence the prenatal environment before the baby is born, possibly increasing the risk for eczema.

Maternal nutrition

Maternal diet during pregnancy and breastfeeding is gaining recognition as an important factor in the pathogenesis of eczema. Current research is vast, with multiple factors including breastfeeding, supplements, vitamin and mineral status playing a potential role in eczema. Below is a summarized list of evidence for the role of maternal nutrition in eczema:

  • Eczema improved after breastfeeding mothers removed eggs and cows’ milk from their diets[10]
  • Mothers who ate a high vegetable diet during pregnancy had two year olds with a lower risk of eczema[11]
  • Probiotic supplementation during pregnancy may reduce eczema in babies[12,13]
  • Mothers who took a vitamin E supplement during pregnancy had a significantly reduced risk for having babies that developed eczema[14]

Breastfeeding and protection against eczema

Overall, there is conflicting evidence regarding whether or not breastfeeding prevents eczema. Although there is a greater majority of evidence supporting that breastfeeding prevents eczema,[15,16] evidence also exists that failed to show a connection.[17,18]

Maternal age and risk for eczema remains unclear

Some research suggests that mothers over the age of 35 years old have an increased risk for having babies who develop eczema,[19] while other research found no connection between maternal age and risk for eczema.[20]

Tobacco and alcohol increase the risk for eczema

  • Babies born to mothers who smoked during pregnancy had a doubled risk for developing eczema[21]
  • There is a significant association between maternal alcohol consumption during pregnancy and having a baby that develops eczema[22]

Family socioeconomic status

There is a common link between low socioeconomic status, such as poverty and inconsistent parenting situations, and poor health in children and adolescents.  Interestingly, eczema is quite the opposite. Researchers have found that parents with higher socioeconomic status (higher income and resources) have an increased risk for eczema in their children.[23,24] These results are surprising, and one hypothesis may be that children born into a lower socioeconomic status may be exposed to more microbes and infections that leads to greater development of the immune system, something referred to as the hygiene hypothesis.[25]

Furry friends prevent eczema

If your child with eczema is asking for a puppy, you may want to give in and get one! Some evidence suggests that early exposure to furry pets actually reduces the risk for developing eczema.[26] Studies have shown protective effects in families with dogs, while some evidence shows that early exposure to cats is not protective against eczema.[27]

 

Bottom Line

As you can see, there are many factors contributing to eczema and research continues to reveal further internal and environmental contributors. There is an undeniable genetic association in eczema, especially in children who have one or more parents with eczema. However, there is still a lot to learn in terms of specific genes and heritability patterns. By understanding the environmental factors that contribute to eczema, doctors can help parents to identify and modify lifestyle factors that may help to improve symptoms in their children.  

           

Table 1 - Genetic and Environmental Factors in Eczema

Genetic Factors

Filaggrin mutation

Increased risk for eczema in children with a mother carrying a filaggrin gene mutation

Chromosome associations

Eczema may be inherited through genes located on certain chromosomes, although specific genes and heritability patterns are still under investigation

Environmental Factors

Maternal Nutrition

During pregnancy, high vegetable diet, probiotic supplementation, and vitamin E supplementation associated with reduced risk of eczema in babies.

Breastfeeding

Although still controversial, a majority of evidence shows breastfeeding for at least 3 months may reduce the risk for eczema

Tobacco

Babies born to mothers who smoked cigarettes during pregnancy had increased risk for eczema

Alcohol

Babies born to mothers who drank alcohol during pregnancy had increased risk for eczema

Socioeconomic status

Higher socioeconomic status associated with increased risk for eczema

Pets

Early exposure to dogs reduces the risk for eczema, while early exposure to cats does not appear to offer a protective benefit

* This Website is for general skin beauty, wellness, and health information only. This Website is not to be used as a substitute for medical advice, diagnosis or treatment of any health condition or problem. The information provided on this Website should never be used to disregard, delay, or refuse treatment or advice from a physician or a qualified health provider.

See additional information.

References

  1. Nutten S. Atopic dermatitis: global epidemiology and risk factors. Ann Nutr Metab.2015;66 Suppl 1:8-16; PMID: 25925336 Link to research.
  2. Boguniewicz M, Leung DY. Atopic dermatitis: a disease of altered skin barrier and immune dysregulation. Immunol Rev.2011;242(1):233-246; PMID: 21682749 Link to research.
  3. Barnes KC. An update on the genetics of atopic dermatitis: scratching the surface in 2009. J Allergy Clin Immunol.2010;125(1):16-29 e11-11; quiz 30-11; PMID: 20109730 Link to research.
  4. Esparza-Gordillo J, Matanovic A, Marenholz I, et al. Maternal filaggrin mutations increase the risk of atopic dermatitis in children: an effect independent of mutation inheritance. PLoS Genet.2015;11(3):e1005076; PMID: 25757221 Link to research.
  5. Ruiz RG, Kemeny DM, Price JF. Higher risk of infantile atopic dermatitis from maternal atopy than from paternal atopy. Clin Exp Allergy.1992;22(8):762-766; PMID: 1525695 Link to research.
  6. Uehara M, Sugiura H, Omoto M. Paternal and maternal atopic dermatitis have the same influence on development of the disease in children. Acta Derm Venereol.1999;79(3):235; PMID: 10384928 Link to research.
  7. Lee YA, Wahn U, Kehrt R, et al. A major susceptibility locus for atopic dermatitis maps to chromosome 3q21. Nat Genet.2000;26(4):470-473; PMID: 11101848 Link to research.
  8. Beyer K, Nickel R, Freidhoff L, et al. Association and linkage of atopic dermatitis with chromosome 13q12-14 and 5q31-33 markers. J Invest Dermatol.2000;115(5):906-908; PMID: 11069631 Link to research.
  9. Bradley M, Soderhall C, Luthman H, et al. Susceptibility loci for atopic dermatitis on chromosomes 3, 13, 15, 17 and 18 in a Swedish population. Hum Mol Genet.2002;11(13):1539-1548; PMID: 12045207 Link to research.
  10. Gerrard JW. Allergy in breast fed babies to ingredients in breast milk. Ann Allergy.1979;42(2):69-72; PMID: 570364 Link to research.
  11. Beckhaus AA, Garcia-Marcos L, Forno E, et al. Maternal nutrition during pregnancy and risk of asthma, wheeze, and atopic diseases during childhood: a systematic review and meta-analysis. Allergy.2015;70(12):1588-1604; PMID: 26296633 Link to research.
  12. Pelucchi C, Chatenoud L, Turati F, et al. Probiotics supplementation during pregnancy or infancy for the prevention of atopic dermatitis: a meta-analysis. Epidemiology.2012;23(3):402-414; PMID: 22441545 Link to research.
  13. Rautava S, Kainonen E, Salminen S, et al. Maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of eczema in the infant. J Allergy Clin Immunol.2012;130(6):1355-1360; PMID: 23083673 Link to research.
  14. Martindale S, McNeill G, Devereux G, et al. Antioxidant intake in pregnancy in relation to wheeze and eczema in the first two years of life. Am J Respir Crit Care Med.2005;171(2):121-128; PMID: 15531754 Link to research.
  15. Schoetzau A, Filipiak-Pittroff B, Franke K, et al. Effect of exclusive breast-feeding and early solid food avoidance on the incidence of atopic dermatitis in high-risk infants at 1 year of age. Pediatr Allergy Immunol.2002;13(4):234-242; PMID: 12390439 Link to research.
  16. Snijders BE, Thijs C, Dagnelie PC, et al. Breast-feeding duration and infant atopic manifestations, by maternal allergic status, in the first 2 years of life (KOALA study). J Pediatr.2007;151(4):347-351, 351 e341-342; PMID: 17889066 Link to research.
  17. Miyake Y, Tanaka K, Sasaki S, et al. Breastfeeding and atopic eczema in Japanese infants: The Osaka Maternal and Child Health Study. Pediatr Allergy Immunol.2009;20(3):234-241; PMID: 19438982 Link to research.
  18. Benn CS, Wohlfahrt J, Aaby P, et al. Breastfeeding and risk of atopic dermatitis, by parental history of allergy, during the first 18 months of life. Am J Epidemiol.2004;160(3):217-223; PMID: 15257994 Link to research.
  19. Olesen AB, Ellingsen AR, Larsen FS, et al. Atopic dermatitis may be linked to whether a child is first- or second-born and/or the age of the mother. Acta Derm Venereol.1996;76(6):457-460; PMID: 8982411 Link to research.
  20. Peters TJ, Golding J. The epidemiology of childhood eczema: II. Statistical analyses to identify independent early predictors. Paediatr Perinat Epidemiol.1987;1(1):80-94; PMID: 3506193 Link to research.
  21. Schafer T, Dirschedl P, Kunz B, et al. Maternal smoking during pregnancy and lactation increases the risk for atopic eczema in the offspring. J Am Acad Dermatol.1997;36(4):550-556; PMID: 9092740 Link to research.
  22. Wada K, Konishi K, Tamura T, et al. Alcohol Intake During Pregnancy and Offspring's Atopic Eczema Risk. Alcohol Clin Exp Res.2016;40(5):1037-1043; PMID: 27062380 Link to research.
  23. Uphoff E, Cabieses B, Pinart M, et al. A systematic review of socioeconomic position in relation to asthma and allergic diseases. Eur Respir J.2015;46(2):364-374; PMID: 25537562 Link to research.
  24. Williams HC, Strachan DP, Hay RJ. Childhood eczema: disease of the advantaged? BMJ.1994;308(6937):1132-1135; PMID: 8173454 Link to research.
  25. Flohr C, Yeo L. Atopic dermatitis and the hygiene hypothesis revisited. Curr Probl Dermatol.2011;41:1-34; PMID: 21576944 Link to research.
  26. Langan SM, Flohr C, Williams HC. The role of furry pets in eczema: a systematic review. Arch Dermatol.2007;143(12):1570-1577; PMID: 18087010 Link to research.
  27. Brunekreef B, Von Mutius E, Wong G, et al. Exposure to cats and dogs, and symptoms of asthma, rhinoconjunctivitis, and eczema. Epidemiology.2012;23(5):742-750; PMID: 22828662 Link to research.