The
phototoxic effects of bergamot essential oil have been known for more than a century. In 1925, Rosenthal coined the term "Berloque dermatitis" (from the French word "breloque" meaning trinket or charm) to describe the pendant-like streaks of pigmentation observed on the neck, face, and arms of patients. He was unaware that, in 1916, Freund had correctly observed that these pigmentation effects were due to sun exposure after the use of
Eau de Cologne, a perfume infused with bergamot oil. Use of bergamot
aromatherapy oil, followed by exposure to
ultraviolet light (either sunlight or a
tanning bed), has been reported to cause
phytophotodermatitis, a serious skin inflammation indicated by painful
erythema and
bullae on exposed areas of the skin. In one case, six drops of bergamot aromatherapy oil in a bath followed by 20–30 minutes exposure of ultraviolet light from a tanning bed caused a severe burn-like reaction. Bergamot essential oil contains a significant amount of
bergapten, a phototoxic substance that gets its name from the
bergamot orange. Bergapten, a linear
furanocoumarin derived from
psoralen, is often found in plants associated with phytophotodermatitis. When bergamot essential oil is applied directly to the skin via a
patch test, followed by exposure to
ultraviolet light, a concentration-dependent
phototoxic effect is observed. However, if the oil is twice rectified (and therefore bergapten-free), no phototoxic response is observed. The
International Fragrance Association (IFRA) restricts the use of bergamot essential oil due to its phototoxic effects. Specifically, IFRA recommends that leave-on skin products be limited to 0.4% bergamot oil, == Notes ==