Introduction

In aromatherapy and massage practices, nut oils are favoured mediums. However, recent research findings that suggest it may be through skin exposure to nut proteins during infancy that nut sensitisation occurs, raises safety concerns for anyone using massage with babies and infants.

Causes for the apparent increase in peanut allergy in children

Most individuals with peanut allergy avoid eating both the nuts and the oil. However, as highly processed oils are generally considered not to contain protein, it is assumed that for the vast majority of peanut allergic people, these are safe to consume. (1,2) Not all experts agree with this view, especially in the case of infants and children; researchers in 1994 reported four cases where peanut oil was shown to worsen an eczematous rash, although it was not specified whether the oil was refined. (3) Differences in the way peanuts are prepared may be contributing to both the increasing prevalence and geographic variability of allergy. Most peanuts in the US are dry roasted, whereas peanuts in China, where peanut allergy is rare, are typically boiled or fried. The higher temperature required for dry-roasting increases the allergenicity of the three major peanut proteins more than the lower temperature used for boiling or frying. (4)

The specific causes of the rising prevalence of peanut allergy and the reasons it appears to be confined to westernised countries remain uncertain.  Maternal diets are often cited as playing a role.  As reactions require previous exposure for sensitisation to occur, it has been suggested that peanut protein is encountered in utero or through breast milk. (5)

However, some researchers hold the view that food avoidance strategies in pregnancy have no effect on sensitisation. According to research by Gideon Lack et al of St Mary's Hospital, Imperial College London, maternal ingestion of peanuts and tree nuts whilst pregnant and/or breastfeeding is not the cause of increased allergies. (6) Rather, Lack suggests, it is the use of skin creams containing peanut oil, to treat nappy rash, eczema or other inflammatory skin conditions in babies, which may lead to childhood peanut allergy.

Skin inflammation favours sensitisation

When the skin is damaged, for example in eczema, large numbers of immunologically active cells are exposed to allergenic substances. Lack's study found, that children with inflamed skin conditions had higher rates of allergy.  The worse the condition, the more likely the allergy, suggesting that exposure through inflamed skin is a cause of sensitisation. Interviews with parents revealed that almost all of the children with confirmed peanut allergy were exposed to creams containing peanut oil in their first six months. Overall, these preparations increased the risk of allergy seven times. In addition, other children with peanut allergy were exposed as infants to a significantly greater number of skin products containing peanut oil compared to atopic and normal controls. According to Lack even refined peanut oil may contain ultra-low levels of peanut proteins that could be sufficient to elicit a positive sensitisation response in certain infants and young children.

Which oils are safe?

Vegetable oils used in aromatherapy and massage, are produced from a botanically diverse range of plant species.  There is a high incidence of sensitivity to multiple nut species, with nut allergens showing frequent cross-reactivity with other food and pollen allergens. (7) Unlike grass pollen allergy where cross-reactivity has been identified as being botanically related, nut allergy does not seem to follow such relationships, making it impossible to predict accurately cross-reactivity. Therefore, in the case of a history of nut allergy, it is advisable to assume allergy to a range of nuts and seeds and be guided in massage oil use by the avoidance of those from known allergenic plants.

In view of the increasing prevalence of childhood allergy and the potentially fatal consequences, anyone using oils should be very cautious in using nut and seed oils with children.  Following Lack's work and the suggestion that allergy may occur through repeated applications of nut oils to inflamed skin, these circumstances demand particular care:

• In the case of nut or food allergic individuals
• Where there is a family history of nut or food allergy, asthma, hay fever or eczema
• On broken or inflamed skin, for example nappy rash
• In the case of atopic children, extreme care should be taken to avoid oil from the skin of other family members or carers touching the skin of the child

Massage oils that are suitable alternatives include:

• Borage
  
• Coconut (fractionated)
  
• Evening primrose
  
• Grapeseed
  
• Jojoba 
• Safflower  
• Conclusion

For therapists there is a particular need to be vigilant and knowledgeable about the risks of using nut oils in massage or aromatherapy. As there are still many unanswered questions in this area, a cautious approach would seem sensible at this stage, to avoid inadvertently contributing to the development of nut-allergy in infants, through topical use of nut-based preparations. 

References

1. Hourihane JO, et al, An evauluation of the sensitivity of subjects with peanut allergy to very low doeses of peanut protein: a randomised, double-blind, placebo-controlled food challenge study. J of Allergy and Clin Immunol 1997; 100:596-600
2. Crevel RWR, et al, Allergenicity of refined vegetable oils. Food and chemical toxicology 2000; 38:385-393
3. Moneret-Vautrin DA, et al,  Risk of formulas containing peanut oil contaminated with peanut allergens in infants with atopic dermatitis. Paed Allergy  Immunol 1994; 5:184-188 cited in Crevel RWR, et al, Allergenicity of refined vegetable oils. Food and chemical toxicology 2000; 38:385-393
4. Beyer K, et al, Effects of cooking methods on peanut allergenicity. J Allergy Clin Immunol 2001; 107:1077-1081
5. Vadas P, et al, Detection of peanut allergens in breast milk of lactating women. JAMA 2001; 285:1746-1748.
6. Lack G, et al, Factors associated with the development of peanut allergy in childhood. N Eng J Med 2003; 348:977-985   
7. Roux KH, et al, Tree nut allergens Int Arch Allergy Immunol 2003; 131:234-244

Hourihane JO, et al, An evauluation of the sensitivity of subjects with peanut allergy to very low doeses of peanut protein: a randomised, double-blind, placebo-controlled food challenge study. J of Allergy and Clin Immunol 1997; 100:596-600

• Crevel RWR, et al, Allergenicity of refined vegetable oils. Food and chemical toxicology 2000; 38:385-393
• Moneret-Vautrin DA, et al,  Risk of formulas containing peanut oil contaminated with peanut allergens in infants with atopic dermatitis. Paed Allergy  Immunol 1994; 5:184-188 cited in Crevel RWR, et al, Allergenicity of refined vegetable oils. Food and chemical toxicology 2000; 38:385-393
• Beyer K, et al, Effects of cooking methods on peanut allergenicity. J Allergy Clin Immunol 2001; 107:1077-1081
• Vadas P, et al, Detection of peanut allergens in breast milk of lactating women. JAMA 2001; 285:1746-1748.
• Lack G, et al, Factors associated with the development of peanut allergy in childhood. N Eng J Med 2003; 348:977-985  
• Roux KH, et al, Tree nut allergens Int Arch Allergy Immunol 2003; 131:234-244

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