Acute radiation dermatitis is a common adverse reaction
of RT which may cause itching, pain, mild erythema, dry
desquamation, moist desquamation with bullae formation
and tissue ulceration leading to tissue fibrosis or even
necrosis in the radiation portal. This dose limiting reaction
may not only impair patient’s quality of life but may
necessitate discontinuation of treatment which may have
adverse effects on clinical outcomes as well [
1].
The prophylactic treatment of acute radiation dermatitis
varies between different radiation oncology centers. Although
various types of agents have been used, a standard
of care has not been addressed yet. One of those agents is
the extracts of aloe vera plant which has been used in gel
or aqueous cream forms. In their randomized controlled
trial Olsen et al. [8] reported that aloe vera gel and mild
soap combination was superior to mild soap alone in
preventing skin reactions in patients undergoing RT. Heggie
et al. [9] reported that the aqueous form of aloe vera was
more effective than gel form. On the other hand Williams
et al. [5] reported that aloe vera gel was ineffective in
prevention of acute radiation dermatitis. As it can be seen,
results of the trials involving aloe vera are conflicting, and
its usage for prevention or treatment of acute radiation
dermatitis remains to be answered.
The case presented here was a part of randomized
controlled trial which was designed to compare topical
usage of aqueous form of aloe vera cream alone or in
conjunction with steroid cream in prevention of acute
radiation dermatitis. In general, when RT is used alone and
in conventional dose schedules without any chemotherapeutic
intervention, type of acute radiation dermatitis
experienced is in the form of initial mild hyperemia beginning
in 24 hours of first treatment which may be progressive
till a total dose of 10-20 Gy [7,10]. More severe reactions are generally experienced when further total doses are
reached. Our patient presented with a more severe form
reported as RTOG grade 3 just in the third day of RT (6
Gy). Negativity of patch test for aloe vera, and local
involvement of lesions instead of being wide spread as in
the case of drug reactions, was important tools for eradicating
possibility of reaction induced by aloe vera itself. Again
as patient was treated with prednisolone successfully and
absence of no further toxicity during remaining course of
radiation therapy in the absence of aloe vera was important
for eradication of radiation induced skin toxicity. Depending
on those factors, the reaction that we experienced was
thought to be caused by an atypical interaction between
RT and aloe vera.
Extracts of aloe vera contains compounds like saponins,
naftaquinones, anthraquinones, sterols and triterpenoids
[11]. Although it is difficult to speculate any mechanism
to explain this interrelated phenomenon caused by radiation
and aloe vera it is possible that each of these constituents
may be responsible for an unknown cascade of reactions
causing the toxicity that we reported here.
We believe that our report is important for two reasons,
first, up to our knowledge, it is the first case reporting this
atypical interaction between aloe vera and RT, and second,
it may serve as a guide for treatment of such a toxicity
when experienced.
In conclusion, we believe that, in the future the prevention
of acute radiation dermatitis could gain greater importance,
as more frequent use of hyperfractionated RT schedules
and concomitant use of chemotherapy will most likely
increase the incidence of such reactions. We recommend
other authors to be more careful and aware of possibility
of such atypical reactions when trials are designed for
seeking better preventive measures of radiation induced
skin toxicity.
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