Lavender Oils May Induce Breast Woes in Young Boys - CME Teaching Brief® - MedP

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Lavender Oils May Induce Breast Woes in Young Boys

By , Senior Staff Writer, MedPage Today

Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of

Pennsylvania School of Medicine.

January 31, 2007

Additional General Endocrinology Coverage

DENVER, Jan. 31 -- Three cases of pre-pubescent gynecomastia in young boys

have raised red flags about the estrogenic-like and anti-androgenic effects

of tea tree oil and lavender, two additives in soaps and lotions.

Action Points

Explain to parents that gynecomastia in young boys is rare and often

associated with an underlying pathology that must be investigated.

Point out that this study suggests that some cases are associated, however,

with use of lavender and tea tree oils in lotions and soaps.

Gynecomastia at puberty is common -- about 60% of boys are affected -- but

it is rare before puberty and is usually considered pathological, according

to Clifford Bloch, M.D., of the University of Colorado School of Medicine.

But in these cases, the culprits were popular soaps, shampoos, and lotions

containing the oils, Dr. Bloch and colleagues reported in the Feb. 1 issue

of the New England Journal of Medicine.

" Since there was no identifiable cause for prepubertal gynecomastia in the

three patients we reported, " Dr. Bloch said, " we speculated that

environmental factors might be contributing to their condition. "

The first clue, he said, was that stopping the use of the various products

caused the enlarged breasts to return to normal within a few months.

To confirm that idea, researchers from the National Institute of

Environmental Health Sciences (NIEHS) in Research Triangle Park, N.C.,

conducted a series of in vitro tests on both oils.

The results " confirm that pure lavender and tea tree oils can mimic the

actions of estrogens, " said Ken Korach, Ph.D., of the NIEHS. Also, he said,

the oils inhibit the effect of androgens.

" This combinatorial activity makes them somewhat unique as endocrine

disruptors, " Dr. Korach said.

In the three reported cases -- four, seven, and 10 year old boys -- all had

normal serum concentrations of endogenous steroids and none had been exposed

to any known outside endocrine disruptors, such as medications, oral

contraceptives, marijuana, or soy products, Dr. Bloch and colleagues

reported.

The finding should alert doctors treating young boy who present with

gynecomastia, said pediatric endocrinologist Henry Anhalt, D.O., of St.

Barnabas Medical Center in Livingston, N.J.

" Tea tree oil and lavender oil and a whole host of other herbal products

have been identified to have primarily estrogen-like activity, " Dr. Anhalt

said, and should be avoided.

In pre-pubescent boys, gynecomastia is often associated with

estrogen-producing tumors, so " the search for the cause becomes something of

great urgency, " said Dr. Anhalt, who was not involved with the study.

He said physicians need to be aware of the possibility of endocrine

disruption in their patients, especially because in some cases it may cause

changes in DNA in the germ cells.

Echoing Dr. Anhalt's comments, Dr. Korach said: " We want to encourage

doctors who may be seeing patients with gynecomastia to ask their patients

about the products they are using. "

He added that while the association has been confirmed, it's not known how

strong the effect is. " Further research is needed to determine the

prevalence of prepubertal gynecomastia in boys using products containing

lavender and tea tree oils, " Dr. Korach said.

The research was supported by the National Institute of Environmental Health

Sciences. Dr. Bloch reported grant support and lecture fees from Eli Lilly,

Genentech, Novo Nordisk, Pfizer, Tercica, and Serono. No other potential

conflict of interest was reported.

Additional General Endocrinology Coverage

Earn CME/CE credit for reading the news.

Primary source: New England Journal of Medicine

Source reference:

Henley DV et al. " Prepubertal Gynecomastia Linked to Lavender and Tea Tree

Oils. " N Engl J Med 2007;356:479-85.

http://www.medpagetoday.com/Endocrinology/GeneralEndocrinology/dh/4973