J Investig Allergol Clin Immunol 2019; Vol. 29(5): 378-398
© 2019 Esmon Publicidad
Manuscript received January 29, 2019; accepted for publication
April 23, 2019.
Guacimara Lucía Hernández-Santana
Hospital Universitario La Candelaria
Carretera del Rosario s/n
38010 Santa Cruz de Tenerife (Canary Islands) Spain
The patient was diagnosed with coconut allergy and
prescribed a strict avoidance diet and autoinjectable adrenaline.
Nevertheless, she presented with a new episode of anaphylaxis
after inadvertent contact with coconut and required adrenaline
and emergency care.
As she went to Thailand every year and spent some months
there, avoiding coconut was very difficult for her. In Thailand,
coconut is a ubiquitous allergen that is found in sauces, soups,
desserts, and bakery. Therefore, we proposed desensitization.
The protocol and adverse reactions and management are
summarized in theTable. For the first phase, we used commercial
coconut milkAroy-D (60% coconut in water) administered with
dose increases every 24 hours. The second phase was performed
with increasing doses of grated coconut (Hacendado) at 48-hour
intervals, with maintenance of the dose reached safely at home,
until a dose of 6 g was reached. No reactions appeared during
this phase.Amaintenance dose of 6 g of grated coconut (0.4 g of
protein) was prescribed 3-4 times per week. We did not increase
the dose in order to avoid excess fat intake.
Today, 2 years after finishing the tolerance induction
procedure, the patient maintains a regular intake of 6 g of
grated coconut 3-4 times per week and follows an open
diet, thus enabling the intake of any food with coconut as an
ingredient, but not coconut itself. She has not presented new
reactions. In a recent assessment, specific IgE levels to coconut
had decreased to 1.98 kU
Coconut is a tropical fruit obtained from the palm tree
, which belongs to theArecaceae family and is also
knownas treenut.Coconut andproductsobtained fromit arewidely
used in the food industry, as well as in body care products and
medicines. Asian countries are leading consumers and exporters.
Coconut is an oval fruit that measures about 20-30 cm
and weighs around 2.5 kg. It consists of a thick outer shell
(exosperm), a thick intermediate layer (mesocarp), and a
hard inner layer (endocarp) to which the pulp (endosperm) is
attached. The endosperm is the edible part of this white and
aromatic fruit. The internal space houses the coconut water.
The endosperm contains a high percentage of globulins and
a smaller percentage of albumins. The 2 globulins described
as food allergens to date are 7S (Coc n 2) and 11S (Coc n 4),
also known as cocosin .
Owing to sensitization to these proteins, cases of cross-
reactivity have been reported between coconut, walnuts,
hazelnuts, and lentils [2,4,5]. Monosensitization to coconut
has also been reported .
In the present case, allergenic proteins were not identified,
although taking into account the molecular weights of the
detected bands, some could correspond to subunits of 7S
globulin (156-kDa, 24-kDa, 22-kDa, and 16-kDa). Protein
sequencing may have helped to identify the culprit allergens.
At present, avoidance is the recommended treatment
for coconut allergy. Such a measure could considerably
impact quality of life in some cultures owing to widespread
consumption, with the consequent risk of accidental contact.
Oral tolerance has been successfully induced to treat food
allergy, mainly to milk, egg, and peanut. For other foods, there
are only single case reports. To our knowledge, this is the first
report of desensitization to coconut. As sensitization profiles
vary from patient to patient, we do not know whether patients
sensitized to proteins such as cocosin would respond in the
same way. Data on desensitization to milk and egg suggest
that high titers of specific IgE against casein and ovomucoid
correlate with a poorer outcome of desensitization . A
similar phenomenon may occur with coconut and other foods.
Nevertheless, we think that desensitization should always be
taken into consideration when a patient presents severe allergy
to a food that is widely present in his or her environment.
The authors declare that no funding was received for the
Conflicts of Interest
The authors declare that they have no conflicts of interest.
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