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Allergic Reaction to Mint Leads to Asthma


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Respiratory and cutaneous adverse reactions to mint can result from several different mechanisms including IgE-mediated hypersensitivity, delayed-type hypersensitivity (contact dermatitis), and nonimmunologic histamine release. Reactions to cross-reacting plants of the Labiatae family, such as oregano and thyme, as well as to the chemical turpentine, may clue the clinician in on the diagnosis of mint allergy. Contact dermatitis can result from menthol in peppermint. Contact allergens have been reported in toothpastes, which often are mint-flavored. Allergic asthma from mint is less well-recognized. A case of a 54-year-old woman with dyspnea on exposure to the scent of peppermint is presented in whom mint exposure, as seemingly innocuous as the breath of others who had consumed Tic Tac candies, exacerbated her underlying asthma. This case highlights the importance of testing with multiple alternative measures of specific IgE to mint, including skin testing with mint extract, and skin testing with fresh mint leaves. Additionally, this cases suggests that asthma can result from inhaling the scent of mint and gives consideration to obtaining confirmatory pre- and postexposure pulmonary function data by both impulse oscillometry and spirometry.
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Allergic reaction to mint leads to asthma
Anthony M. Szema, M.D., and Tisha Barnett, B.S.
Respiratory and cutaneous adverse reactions to mint can result from several different mechanisms including IgE-mediated
hypersensitivity, delayed-type hypersensitivity (contact dermatitis), and nonimmunologic histamine release. Reactions to
cross-reacting plants of the Labiatae family, such as oregano and thyme, as well as to the chemical turpentine, may clue the
clinician in on the diagnosis of mint allergy. Contact dermatitis can result from menthol in peppermint. Contact allergens have
been reported in toothpastes, which often are mint-flavored. Allergic asthma from mint is less well-recognized. A case of a
54-year-old woman with dyspnea on exposure to the scent of peppermint is presented in whom mint exposure, as seemingly
innocuous as the breath of others who had consumed Tic Tac candies, exacerbated her underlying asthma. This case highlights
the importance of testing with multiple alternative measures of specific IgE to mint, including skin testing with mint extract,
and skin testing with fresh mint leaves. Additionally, this cases suggests that asthma can result from inhaling the scent
of mint and gives consideration to obtaining confirmatory pre- and postexposure pulmonary function data by both
impulse oscillometry and spirometry.
(Allergy Rhinol 2:43–45, 2011; doi: 10.2500/ar.2011.2.0008)
Although food allergy reactions are becoming in-
creasingly recognized,
adverse reactions on
exposure to the mint plant and products containing
mint and related plants are often unrecognized. We
present a case of a newspaper reporter who wheezed
when interviewing persons eating Tic Tac mint candy
(Ferrero, USA).
The patient is a 54-year-old woman with the chief
complaint, “I can’t breathe near mint.” Additionally,
she has noted for the past year that her “right lung
hurts near mint.” When persons at work chew Tic Tacs
(mints), she gets short of breath. In the context of her
duties as a New York City reporter, she interviews
many people, less than an arm’s length away, who
consume mints. Her asthma inhaler does not help with
one puff. She has noted a significant exposure history
to a mint garden, which she played in for hours at a
time as a child, every summer. Mint-scented cleaning
fluids make her shortness of breath worse.
Collateral allergic history is notable for seasonal al-
lergic rhinitis because of known tree pollen allergy.
Physical examination was unremarkable. Laboratory
evaluation including pulmonary function tests and as-
sessment for specific IgE to peppermint is shown in
Tables 1–3 and Fig. 1.
In evaluating a patient who experiences severe exac-
erbations of asthma (without rash) near mint-contain-
ing products, what workup is most appropriate if
serological measurement of specific IgE to mint is neg-
A. Skin test to mint extract and obtain pre- and post-
lung function measurements on exposure to mint.
B. Patch test with menthol and peppermint to be in-
terpreted on day 5 (D5).
C. Ask patient about reactions to oregano, thyme, and
D. Refer patient for psychiatric consultation.
The literature reports infants and children with con-
tact dermatitis from menthol in peppermint.
allergens have been reported in toothpastes, which
often are mint-flavored.
Also, turpentine-induced
sensitivity to peppermint oil has been noted.
D5 patch
test reactions to menthol and peppermint are an avail-
able option.
Dental screening patch testing has been
Contact sensitivity to menthol and pepper-
mint has been reported in patients with intraoral
In addition, systemic reactions to ingestion of oreg-
ano and thyme are further related, because these and
mint belong to the Labiatae family.
Skin tests with
inhalants in a group of patients in one study were
positive to grasses and with plants of the Labiatae
From State University of New York at Stony Brook School of Medicine, Stony Brook,
New York
The authors have no conflicts to declare pertaining to this article
Address correspondence and reprint requests to Anthony M. Szema, M.D., Stony
Brook Allergy & Asthma, Stony Brook Medical Perk, 2500 Nesconset Highway, Suite
17A, Stony Brook, NY 11790
E-mail address:
Copyright ©2011, OceanSide Publications, Inc., U.S.A.
Allergy & Rhinology 43
family, which comprises other plants such as mint
(Mentha piperita) as shown in Fig. 2. Thus, plants be-
longing to the Labiatae family seem to show cross-
sensitivity based on clinical history and in vitro and in
vivo test results.
Histamine release caused by pepper-
mint can also depend on nonimmunologic mecha-
Allergic asthma from mint is less well recog-
In summary, this 54-year-old woman was symptom-
atic with dyspnea near peppermint and had a positive
skin-prick test to a commercial peppermint extract.
Mint exposure, as seemingly innocuous as Tic Tacs,
exacerbated her underlying asthma. Objective testing
pre- and postexposure to peppermint confirmed re-
duced lung function, suggesting the diagnosis of aller-
gic asthma triggered by mint, in this woman who may
have been sensitized by inhaling mint in her garden as
a child. Impulse oscillometry (IOS), a noninvasive mea-
sure of small airways impedance showed increased
airways resistance from an R5 of 2.2 at baseline, in-
creasing to 4.4. This patient should avoid mint expo-
sure and take albuterol metered-dose inhaler with
This case highlights the importance of testing with
multiple alternative measures of specific IgE to mint,
including skin testing with mint extract and skin testing
with fresh mint leaves. Additionally, this case suggests
that asthma can result from inhaling the scent of mint and
gives consideration to obtaining confirmatory pre- and
postexposure pulmonary function data by both IOS and
spirometry. This case also suggests that serological tests
Table 1 Spirometry pre- and postbronchodilator
Percent Predicted
2.59 88
FVC 3.53 97
/FVC 73%
2.69 92.3
FVC 3.44 99.6
/FVC 78%
forced expiratory volume in 1s; FVC forced vital
Table 2 Pulmonary function testing pre– and
post–mint exposure (inhalation)
2.46 2.46
FVC 3.31 3.31
74% 74%
2.2 (nl) 66.5 4.41# 122
1.6 (nl) 77 2.8 (nl) 88
IOS X5Hz 13.03 2638 18§ 2506
*IOS after inhaling mint and skin prick test. IOS is a
noninvasive way to measure the respiratory system imped-
ance and reliably measures central and peripheral airways
resistance at different oscillation frequencies.
#R5 4.41–8 suggests mild small airways narrowing is
§X5Hz ⫽⫺18 abnormal suggests airway hyperresponsive-
forced expiratory volume in 1 s; FVC forced vital
capacity; IOS impulse oscillometry; nl normal.
Table 3 Testing for specific IgE
In Vitro
Histamine 5/10
Saline 0/0
Fresh mint leaves 0/0
McCormick Pure
Mentha piperita
0.10 KU/L
*McCormick & Company, Inc., Sparks, MD.
Figure 1. Skin test to peppermint: Saline is labeled S to the far left
and is negative; histamine is in the middle and raised a 5-mm wheal
and 2-cm flare. Mint is to the right and raised a 5-mm wheal and
2-cm flare.
44 January–March 2011, Vol. 2, No. 1
for IgE to peppermint are less sensitive than skin-prick
The patient was comforted by having obtained a defin-
itive diagnosis of her symptoms. Previously, she thought
that she was imagining her adverse reactions. It helped
alleviate tension between the patient and her colleagues
and led to the recommendation to take her albuterol
inhaler p.r.n. and avoid situations with exposure to mint.
As allergists/immunologists caring for children and
adults, we have the opportunity to recognize and prevent
adverse reactions from mint exposure. As the aforemen-
tioned case illustrates, these exposures may be previously
unrecognized sources of anxiety and morbidity.
Correct Answer to Question: A and C
Clinical Pearls
Allergic asthma can result from inhaling the scent of
Pre- and post-IOS may be more sensitive than spi-
rometry to assess acute small airways narrowing on
exposure to mint.
Skin testing with mint extract may be more sensitive
than specific serum IgE to mint.
D5 patch testing may determine if a delayed contact
dermatitis to mint is present but does not verify if an
immediate hypersensitivity reaction is present.
Lichenoid oral lesions have been reported with men-
thol mouthwashes.
Reactions to cross-reacting plants such as oregano
and thyme, as well as the chemical turpentine, may
clue in the clinician on the diagnosis of mint allergy.
Clinical Pitfalls
Other physicians dismissed the patient’s complaints
on exposure to mint and did not request skin testing.
Spirometry may be insensitive compared with IOS,
which is not widely available.
Gell-Coombs immediate hypersensitivity (type I) is
tested with the skin-prick test but Gell-Coombs type
IV is assessed with D5 patch testing.
Many dental products contain mint, and even asthma
medication Aerobid M (Forest Laboratories, New
York, NY) contains menthol.
The authors thank Steven Spungen from CareFusion Corp. (Yorba
Linda, CA) for the generous use of a Jaeger Impulse Oscillometer/
Spirometer and exhaustive hands-on technical assistance.
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Figure 2. Peppermint. (Borrowed with permission courtesy of
White Flower Farm, Litchfield, CT.)
Allergy & Rhinology 45
... Allergy (42)(43)(44)(45)(46) or anaphylaxis (47,48) caused by peppermint is not uncommon. Peppermint oil is safe for short-term use ( 4-7 days) as aromatherapy in pregnancy ( 49,50) . ...
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Stomachic mixture is used widely for the treatment of gastrointestinal conditions. However, the evidence for its efficacy and safety is scarce. The review of pharmacology and toxicity of stomachic mixture constituents provides information for patients and healthcare providers in deciding the use of this drug. Stomachic mixture products registered in Thailand as shown in the Thai Food and Drug Administration database in 2018 contained sodium bicarbonate as their main active ingredient of the stomachic mixture. The herbal components in the stomachic recipe registered to Thai FDA were volatile oils, anthraquinone glycosides, bitter substances, and spicy substances. The amount of each ingredient in the stomachic mixture, when the mixture was used as recommended, was lower than toxic doses of the component. However, the sodium amount in the stomachic mixture could be high for patients requiring sodium restriction. Data regarding the use of stomachic mixture in pregnant and lactating women were insufficient. Therefore, the stomachic mixture should be avoided in patients requiring sodium restriction, pregnant women, and breastfeeding women. Side effects of stomachic mixture on the liver, kidney, heart, gastrointestinal tract, and central nervous system and hypoglycemia are possible.
... The majority of these ailments occurred as a result of a positive allergic reaction to peppermint, often accompanied by erythema and topical sensitivity. [135][136][137][138][139][140][141][142][143] Menthone administered to rats at a high dose over 28 days did display some signs of hepatotoxicity and cerebellar histopathology. 66,144 However, as mentioned previously, the significance of this finding may warrant careful interpretation. ...
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Peppermint (Mentha x piperita L.) is not only used as a medicinal plant with therapeutic activity but also as a tea infusion, herb, spice or as a flavoring agent in other preparations. However, its adverse side effects on health have been described. The outcome of this review revealed that peppermint and its main constituents (pulegone, menthone, menthol and menthofuran) are moderately toxic. Peppermint and its menthol isomers possess no major innate mutagenic, genotoxic or embryotoxic properties. Peppermint essential oil interacts with cytochrome P450 isoenzymes in human liver microsomes. It is contraindicated in patients with bile duct obstruction and gall bladder inflammation. In patients with gastrointestinal reflux or hiatus hernia, its use should be exercised with caution because it may exacerbate the symptoms of gastrointestinal reflux.
... Subsequently, skin prick test and provocation challenge with a menthol toothpaste were complicated with rhinoconjuctivitis symptoms, abdominal cramps and wheezing, suggesting multisystem involvement similar to our case report. In most reports published so far, sensitization to peppermint occurred via oral and/or dermal route345678 . In contrast , our patient displayed a unique mode of sensitization to peppermint plant, via airborne peppermint pollen [9]. ...
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Anaphylaxis, a form of IgE mediated hypersensitivity, arises when mast cells and possibly basophils are provoked to secrete mediators with potent vasoactive and smooth muscle contractile activities that evoke a systemic response. We report a case of IgE mediated anaphylaxis to peppermint (Mentha piperita) in a male shortly after sucking on a candy. A 69 year old male developed sudden onset of lip and tongue swelling, throat tightness and shortness of breath within five minutes of sucking on a peppermint candy. He denied lightheadedness, weakness, nausea, vomiting, or urticaria. He took 25 mg of diphenhydramine, but his symptoms progressed to onset of cough, wheeze and difficulty with talking and swallowing. He was rushed to the nearest emergency department, where he was treated with intramuscular epinephrine, antihistamines and steroids. On history, he reported recent onset of mouth itchiness and mild tongue and lip swelling after using Colgate peppermint toothpaste. He denied previous history of asthma, allergic rhinitis, food or drug allergies. His past medical history was remarkable for hypercholesterolemia, gastroesophageal reflux and gout. He was on simvastatin, omeprazole, aspirin, and was carrying a self-injectable epinephrine device. He moved to current residence three years ago and cultivated mint plants in his backyard. He admitted to develop nasal congestion, cough and wheeze when gardening. Physical examination was unremarkable apart from slightly swollen pale inferior turbinates. Skin prick test (SPT) was strongly positive to slurries of peppermint candy and fresh peppermint leaf, with appropriate controls. Same tests performed on five healthy volunteers yielded negative results. Skin testing to common inhalants including molds and main allergenic foods was positive to dust mites. Strict avoidance of mint containing items was advised. Upon reassessment, he had removed mint plants from his garden which led to resolution of symptoms when gardening. IgE mediated anaphylaxis to peppermint is rare. This case demonstrates a systemic reaction to a commonly consumed item, incapable of triggering anaphylaxis in the far majority of the population, yet causing a severe episode for our patient.
... In these populations, the inhalation of menthol may trigger an uncontrolled upper airway muscle reflex resulting in spasms and significant breathing difficulties [56]. Another important side effect of menthol and peppermint formulations is the potential for allergic reactions with the development of skin rashes [57] which can also cause worsening of asthma symptoms in vulnerable populations [58]. The reported data for these side effects, however, remains sparse and is currently limited to case reports. ...
Menthol, a natural product of the peppermint plant Mentha x piperita (Lamiaceae), is a monoterpene which is widely used as a natural product in cosmetics, a flavouring agent, and as an intermediate in the production of other compounds. Various extracts from peppermint contain menthol as a major active constituent and have been used for centuries as traditional medicines for a number of ailments including infections, insomnia, and irritable bowel syndrome as well as an insect repellent. Menthol's characteristic cooling sensation is due, in part, to the activation of sensory neurons generally termed transient receptor potential (TRP) channels, in particular transient receptor potential melastatin family member 8 (TRPM8) and transient receptor potential subfamily A, member 1 (TRPA1). Menthol acts upon TRPM8 receptors by rapidly increasing intracellular calcium and mobilizing calcium flux through the channels to induce cold response signals at the application site. Aside from its cold-inducing sensation capabilities, menthol exhibits cytotoxic effects in cancer cells, induces reduction in malignant cell growth, and engages in synergistic excitation of GABA receptors and sodium ion channels resulting in analgesia. Notwithstanding its plethora of benefits, menthol's cold-sensitivity response mechanism has been shown to inhibit mucosal recognition of nicotine and cigarette toxins common in mentholated cigarette brands thus potentially leading to toxic effects. Menthol may proof a valuable lead structure for the synthesis of drugs that target multiple receptors involved with a number of pharmacological effects.
Résumé Introduction L’huile essentielle de menthe poivrée (Mentha piperita) est surtout composée de menthol (famille des terpènes). De rares cas d’asthmes au menthol ont été décrits, résultant d’un mécanisme IgE médié ou non. Nous rapportons le cas d’une patiente avec un asthme allergique IgE médié à l’huile essentielle de menthe poivrée. Observation Patiente de 43 ans aux antécédents d’asthme et de rhinite allergique aux pollens de graminées et de polypose nasosinusienne qui utilisait des huiles essentielles de différentes plantes. Elle a présenté des crises d’asthme avec un dentifrice mentholé, des bonbons à la menthe et après ingestion d’huile essentielle et de pastilles pour la gorge à la menthe. Les symptômes régressaient après bronchodilatateurs. Le prick-test à l’huile essentielle de menthe poivrée était positif et les contrôles étaient négatifs. Cinq minutes après l’ingestion d’un sucre avec 2 gouttes d’huile essentielle de menthe poivrée, une chute du volume expiré maximum à la première seconde de 88 % de la valeur prédite à 64 % était constatée. Une réversibilité était obtenue 1 h après bronchodilatateurs. Conclusion Il s’agit d’un cas d’asthme allergique IgE médié à l’huile essentielle de menthe poivrée avec une probable sensibilisation par le menthol. Les huiles essentielles peuvent entraîner de véritables asthmes allergiques et doivent donc faire partie du questionnaire environnemental du patient asthmatique.
Tube feeding (TF) is the most common form of nutrition support. In recent years, TF administration has increased among patient populations within and outside hospital settings, in part due to greater insurance coverage, reduced use of parenteral nutrition, and improved formularies suitable for sole source nutrition. With increasing life expectancy and improved access to TFs, the number of adults dependent on enteral nutrition is expected to grow. However, enteral TF intolerance (ETFI) is the most common complication of TFs, typically presenting with at least 1 adverse gastrointestinal event, including nausea, diarrhea, and constipation. ETFI often leads to reductions in TF volume with associated energy and protein deficits. Potentially ensuing malnutrition is a major public health concern due its effects on increased risk of morbidity and mortality, infections, prolonged hospital length of stay, and higher healthcare costs. As such, there is a need for intervention strategies to prevent and reduce ETFI. Incorporating whole foods with bioactive properties is a promising strategy. Emerging research has elucidated bioactive properties of whole foods with specific benefits for the prevention and management of adverse gastrointestinal events commonly associated with TFs. However, lack of evidence-based recommendations and technological challenges have limited the use of such foods in commercial TF formulas. This review addresses research gaps by discussing 5 whole foods (rhubarb, banana, curcumin, peppermint oil, and ginger) with bioactive attributes identified through literature searches and clinical experience as having substantial scientific rationale to consider their application for ETFI in adult populations.
The International Contact Dermatitis Research Group proposes a classification for the clinical presentation of contact allergy. The classification is based primarily on the mode of clinical presentation. The categories are direct exposure/contact dermatitis, mimicking or exacerbation of preexisting eczema, multifactorial dermatitis including allergic contact dermatitis, by proxy, mimicking angioedema, airborne contact dermatitis, photo-induced contact dermatitis, systemic contact dermatitis, noneczematous contact dermatitis, contact urticaria, protein contact dermatitis, respiratory/mucosal symptoms, oral contact dermatitis, erythroderma/exfoliative dermatitis, minor forms of presentation, and extracutaneous manifestations.
Allergic contact dermatitis is a common condition in dermatology. Patch testing is the criterion standard for diagnosis. However, dermatitis is not always caused by an allergen, and patch testing does not identify a culprit in every patient. Generalized dermatitis, defined as eczematous dermatitis affecting greater than 3 body sites, is often encountered in dermatology practice, especially patch test referral centers. Management for patients with generalized dermatitis who are patch test negative is challenging. The purpose of this article is to outline an approach to this challenging scenario and summarize the paucity of existing literature on patch test negative generalized dermatitis.
Food allergy is increasingly common; however, there is a discrepancy between the large number of people who believe they or their children are affected and the actual number with true food allergies. It is therefore imperative that physicians evaluating patients with possible adverse reactions to foods understand the current modalities used to diagnose food allergies. Simple tests including skin-prick testing (SPT) and serum food-specific IgE testing are the most commonly used diagnostic tests to evaluate for IgE-mediated food reactions. However, these tests have pitfalls and their usefulness must be appreciated to avoid over- and underdiagnosis. A firm diagnosis is imperative because a misdiagnosis could lead to life-threatening reactions and overdiagnosis will lead to unnecessary elimination diets with nutritional and social implications. Physician-supervised oral food challenges (OFC) remain the gold standard for food allergy diagnosis; however, a careful medical history and simple tests can often provide a reliable diagnosis. In this review, we examine the usefulness and pitfalls of SPT used by allergists and serum food-specific IgE levels that are available to all practitioners. We also review the OFC as a diagnostic modality in food allergy. Finally, we describe emerging tests, such as the basophil activation test, atopy patch testing, and component-resolved diagnostics, that may be of benefit in the future.
There is little data in the literature regarding outpatient consultation in allergy/immunology (A/I). The purpose of this study was to determine the relative frequency of different reasons for A/I outpatient consultation to help guide graduate medical education (GME) and assist with A/I practice management. We retrospectively reviewed the electronic medical records of all outpatient A/I consultations from January 1, 2006 to December 31, 2006. The study was performed at our tertiary care referral center which is a GME training site. There were 1412 A/I consults requested during the 1-year period. The consults per month ranged from a low of 69 to a high of 157. The referrals consisted of 35% pediatric and 65% adult patients. There were 52.8% female and 47.2% male patients. We received 74.3% of referrals from primary care, 19.8% from specialty care, and 5.9% from the emergency department. The most common reasons for consultation included 808 (57.2%) patients for chronic rhinitis, 288 (20.4%) for asthma, 196 (13.9%) for food allergy, 89 (6.3%) for venom allergy, 68 (4.8%) for atopic dermatitis, 66 (4.7%) for drug allergy, 62 (4.4%) for chronic urticaria, 45 (3.2%) for acute urticaria, 34 (2.4%) for immunodeficiency, 31 (2.2%) for anaphylaxis, and 162 (11.5%) for other reasons. More than one reason was given for 27.1% of consults, and there was an average of 1.3 reasons for consultation per patient. Although the allergist/immunologist is consulted for a variety of reasons, the top three reasons make up a majority of outpatient consults, and consults are often requested to address more than one diagnosis.
After a dental operation a former laboratory technician was referred to our clinic because of swelling of his tongue, lips, and gingival mucosa. Patch testing with the ICDRG standard test battery gave positive reactions to colophony, balsam of Peru, and turpentine peroxides. Further patch testing revealed hypersensitivity to peppermint oil (an ingredient of several dental preparations) due to the sensitizing properties of three ingredients: alpha-pinene, limonene, and phellandrene. These compounds also occur in turpentine oil, a substance used in the patient's laboratory.
Toothpaste flavors are fragrance mixtures. Oil of peppermint and spearmint, carvone and anethole are ingredients with a low sensitizing potential, but they are used in almost every brand of toothpaste and caused seven cases of contact allergy in a 6-year period at Gentofte Hospital. Toothpaste reactions are rare due to several reasons; local factors in the mouth, the low sensitizing potential of the flavors generally used, and the lack of recognition. It is emphasized that the toothpaste battery for patch testing has to be relevant and changed according to the consumers' and manufacturers' taste and fashion.
Allergic and pseudo-allergic reactions were examined in penicillin factory workers exposed to the dust of preparations of pivampicillin and pivmecillinam. Among 14 workers basophils from five persons showed histamine release by challenge with penicillins, whereas no release was observed in controls of non-atopic individuals not working with the manufacturing of penicillin. Positive skin response was obtained in four workers by path testing and in three persons by scratch test revealing late but no immediate response. All the eight workers who were also exposed to flavour additives used in the penicillin preparations showed histamine release by cocoa and peppermint. The release was not changed by removal of immunoglobulins from the basophil cell surface and the additives caused a similar release in the controls. The histamine release caused by cocoa and peppermint therefore depend on non-immunological mechanisms, i.e. pseudo-allergic reactions which might contribute to the symptoms in penicillin factory workers.
We report 12 cases of contact sensitivity to the flavouring agents menthol and peppermint oil in patients presenting with intra-oral symptoms in association with burning mouth syndrome, recurrent oral ulceration or a lichenoid reaction. The patients were referred from the Glasgow Dental Hospital over a 4-year period for assessment of the possible contribution of contact sensitivity to their complaints. 5 patients with burning mouth syndrome demonstrated contact sensitivity to menthol and/or peppermint, with 1 patient sensitive to both agents, 3 positive to menthol only and 1 to peppermint only. 4 cases with recurrent intra-oral ulceration were sensitive to both menthol and peppermint. 3 patients with an oral lichenoid reaction were positive to menthol on patch testing, with 2 also sensitive to peppermint. 9 of the 12 cases demonstrated additional positive patch test results. After a mean follow-up of 32.7 months (range 9-48 months), of the 9 patients that could be contacted, 6 patients described clearance or improvement of their symptoms as a consequence of avoidance of menthol/peppermint.
The present study summarizes information on toothpaste composition as supplied by the manufacturers. The survey covered 48 items, virtually all toothpastes offered for sale in Finland. It was concluded that the toothpastes are not entirely safe to use, because almost 50% of the products studied contained a total of some 30 compounds widely recognized as allergens. According to the literature, the most common allergens in toothpastes are flavours (e.g., cinnamic aldehyde, cinnamon oil and peppermint) and preservatives. Symptoms include stomatitis, cheilitis, glossitis, gingivitis, perioral dermatitis and immediate hypersensitivity.
There are no cases described in the medical literature of systemic allergic reactions due to oregano (Origanum vulgare) or thyme (Thymus vulgaris). These herbs belong to the Lamiaceae (Labiatae) family which comprises other plants such as hyssop (Hyssopus officinalis), basil (Ocimum basilicum), marjoram (Origanum majorana), mint (Mentha piperita), sage (Salvia officinalis) and lavender (Lavandula officinalis). We describe three systemic allergic reactions caused by oregano and thyme in the same patient. Skin tests with inhalant allergens and plants of the Labiatae family were done. We used the prick by prick technique with dried commercial plants and prick tests with extracts prepared with the Frugoni method in our patient and in ten control patients. Total serum IgE was determined by Phadezym IgE PRIST (Pharmacia). Specific IgE was measured by two methods: CAP system (Pharmacia) and Phadezym RAST (Pharmacia Diagnostics, Uppsala, Sweden) with activated discs of the allergenic extracts that were prepared in our laboratory. Skin tests with inhalants were positive to grasses. Skin tests with plants of the Labiatae family were positive in all cases when the skin prick technique was used; tests were negative with basil and lavender, and positive with all the others when we used the prick by prick technique. We did not detect any positive skin tests nor specific IgE to plants of the Labiatae family in control patients. Total serum IgE was 406 U/mL. Specific IgE was detected to all herbs tested; higher levels were obtained with the CAP system. Plants belonging to the Labiatae family seem to show cross-sensitivity on the basis of clinical history and in vitro and in vivo test results.