Ist Teebaumöl giftig?


    Ja, ganz besonders für Katzen! Aber auch beim Menschen sind mittlerweile zahlreiche Vergiftungen beobachtet worden!

    In der veterinärmedizinischen Literatur und auch bei den Menschenärzten gibt es dazu zahlreiche Veröffentlichungen:

    1. Katzenkiller Teebaumöl AHO (www.animal-health-online.de)

    Teebaumöl (Tea Tree Oil), botanischer Name: Melaleuca alternifolia (Myrtaceae) wird sowohl in der Human als auch in der Veterinärmedizin immer beliebter. Dies beruht nicht zuletzt auf der irrigen Annahme, dass "natürlich" zwangsläufig "nebenwirkungsfrei" bedeutet.

    Rasant steigende Verkaufszahlen

    Während der letzten 10 Jahre stieg der Verkauf von Teebaumöl von rund acht auf 150 bis 200 Tonnen jährlich. In Broschüren, Büchern und Anzeigen wird Teebaumöl unter anderem zur Therapie bei Akne, Schuppen und Schuppenflechte, Pilzerkrankungen,

    Muskelschmerzen, offenen Wunden, Rheuma, Raucherhusten und Krampfadern angepriesen (14). Nicht selten wird Teebaumöl völlig verharmlosend beworben, wie das nachfolgende Zitat von einer kommerziellen Internetseite zeigt:

      Teebaumöl ist nebenwirkungsfrei, natürlich und einfach in der Handhabung. Durch die Vielfalt der Anwendungsmöglichkeiten ist es eine natürliche Alternative zu vielen speziellen Präparaten und "chemischen Keulen".


    Hochwirksame Inhaltsstoffe

    Unterzieht man Teebaumöl einer Gaschromatographie, so erkennt man, dass dieser angeblich so harmlose "Naturstoff" ein Gemisch aus einer Vielzahl potenter, pharmakologisch hochwirksamer Substanzen (Terpene und Phenole) ist.

    Beispiel einer Analyse:
      2,6% a-Pinene
      1,01% Limonene
      20,42 % y-Terpinene
      3,1% a-Terpineol
      1,00% d-Cadinene
      0,10% Sabinene
      3,31% p-Cymene
      3,1% Terpinolene
      1,31% Aromadendrene
      0,5% Globulol
      8,4% a-Terpinene
      3,3% 1.8 Cineole
      40,5% Terpinene-4-ol
      0,7% Ledene
      0,4% Viridiflorol

    Da es sich um einen Naturstoff handelt, kann die Zusammensetzung von Produkt zu Produkt und von Charge zu Charge erheblich schwanken. Gelegentlich ist Teebaumöl auch gepanscht, wie eine Untersuchung belegt, die unter der Leitung von Prof. Hans Becker an der Universität Saarbrücken durchgeführt und in der Deutschen Apothekerzeitung im Dezember 97 veröffentlicht wurde.

    Nebenwirkungen
    Gleichzeitig mit der zunehmenden Anwendung werden weltweit Nebenwirkungen bei Mensch und Tier beschrieben. Humanmediziner diagnostizieren häufig eine Kontaktdermatitis oder Allergien (10, 13, 14). Ebenso mehren sich Vergiftungen mit Übelkeit, Durchfällen, Gleichgewichtsstörungen, Müdigkeit und Desorientiertheit bei Kleinkindern (8, 9) und Erwachsenen nach Einnahme von bis zu 10 ml unverdünntem Teebaumöl (11, 12).

    Kritikloser Einsatz
    Teebaumöl wird immer häufiger auch völlig kritiklos bei Katzen z.B. gegen Flöhe eingesetzt, ohne dass sich die Tierbesitzer über die tierartspezifischen Unverträglichkeiten beraten lassen. Folge ist, dass immer wieder Katzen mit "Teebaumöl-Vergiftungen" in der Tierarztpraxis vorgestellt werden. Taumeln, chronische Abmagerung, Zittern, Unruhe, Schwäche (5, 6) sind die nur zu gut bekannten Symptome einer Teebaumöl Vergiftung. Nicht selten endet die Vergiftung mit Koma und Tod der Katze. Werden vergiftete Katzen frühzeitig einem Tierarzt vorgestellt, so können sich die Tiere innerhalb zwei bis drei Tagen erholen (5).

    Warum?
    Durch den Gehalt an Terpenen und Phenolen sind Teebaumöl und viele andere ätherische Öle (Thymian -, Oregano und Zimtöle) für Katzen toxisch. Katzen können durch die fehlende Fähigkeit zur Glucuronidierung (Verstoffwechselung) diese Verbindungen nur sehr langsam ausscheiden (1, 2, 3, 6), die Inhaltsstoffe des Teebaumöls reichern sich im Körper der Katze an, es kommt zur Vergiftung. Selbst wenn Tierbesitzer ihren Katzen nur wenige Tropfen Teebaumöl zur Flohbekämpfung auf das Fell tropfen, so können die Katzen doch bei der Fellpflege toxische Mengen aufnehmen und erkranken.

    Tierschutz
    Insbesondere durch die schwankenden und für den Tierbesitzer schwer zu beurteilenden Inhaltsstoffe, ist eine Anwendung bei der Katze ein unkalkulierbares Risiko und aus Gründen des Tierschutzes abzulehnen. Selbst wenn es im Einzelfall nicht zu sichtbaren Vergiftungserscheinungen kommt, können Langzeitfolgen insbesondere nach wiederholter Anwendung nicht ausgeschlossen werden. Zudem stehen dem Tierarzt eine Vielzahl von zugelassenen und erprobten Arzneimitteln zur Flohbekämpfung zur Verfügung.

    Quellen:
    (1) Kraft, W. u. U.M. Dürr (Hrsg.), Katzenkrankheiten, 4. Aufl.,
    Verlag M. ∓ H. Schaper, 1996.

    (2) Strolin-Benedetti, M.., Les reactions de conjugiasion dans le metabolisme des medicaments, Act. Chim. Ther., 7, S. 357 - 390, 1980

    (3) Ungemach, F. R., Pharmakotherapie des Respirationstraktes, in: Löscher, W., F. R. Ungemach u. R. Kroker, Pharmakotherapie bei Haus und Nutztieren, 3. Aufl., Parey Buchverlag Berlin, 1997 (4) Bischoff K, Guale F, Australean tee tree oil posioning in three purebred cats, Journal of Veterinary Investigation 10(2) S. 208 - 210, 1998 Zusammenfassung in engl. Sprache:
    Three Angora cats with severe flea infestations were shaved and treated with pure M. alternifolia oil (about 120 ml between all 3 cats). Within 5 h of treatment the 2 cats were hypothermic and dehydrated, all developed nervous signs and one was comatose. The cats were bathed in mild detergent, given activated charcoal and dexamethasone orally and the dehydrated cats were given fluid therapy. The comatose cat improved over days 2 and 3 but remained ataxic and obtunded. On day 3 it began regulating it body temperature but died of an undiagnosed caused later that evening. The other 2 cats recovered at 24 and 48 h after treatment.

    (5) Villar D, Knight MJ, Hansen SR, Buck WB
    Toxicity of melaleuca oil and related essential oils applied topically on dogs and cats.
    Vet Hum Toxicol 1994 Apr;36(2):139-42

    Zusammenfassung in engl. Sprache:
    Cases of melaleuca oil toxicosis have been reported by veterinarians to the National Animal Poison Control Center when the oil was applied dermally to dogs and cats. In most cases, the oil was used to treat dermatologic conditions at inappropriate high doses. The typical signs observed were depression, weakness, incoordination and muscle tremors. The active ingredients of commercial melaleuca oil are predominantly cyclic terpenes. Treatment of clinical signs and supportive care has been sufficient to achieve recovery without sequelae within 2-3 d.

    (6) Wynn, S.G., ∓ Kirk-Smith, M.D. "Aromatherapy in veterinary practice." In Schoen, A., ∓ Wynn, S., eds. Complementary and Alternative Veterinary Medicine: Principles and Practice, St. Louis, Mo.: Mosby, 1997.

    (7) Universität Zürich im Internet
    http://www.vetpharm.unizh.ch/script/tox/tox3.html

    (8) Jacobs MR, Hornfeldt CS
    Melaleuca oil poisoning.

    Zusammenfassung in engl. Sprache:
    J Toxicol Clin Toxicol 1994;32(4):461-4

    A 23-month-old boy became confused and was unable to walk thirty minutes after ingesting less than 10 mL of T36-C7, a commercial product containing 100% melaleuca oil. The child was referred to a nearby hospital. His condition improved and he was asymptomatic within 5 hours of ingestion. He was discharged to home the following day. Melaleuca oil, extracted from the Melaleuca alternifolia, contains 50-60% terpenes and related alcohols. Clinical experience with products containing melaleuca oil is limited. This case report suggests that ingestion of a modest amount of a concentrated form of this oil may produce signs of toxicity.

    (9) Del Beccaro MA
    Melaleuca oil poisoning in a 17-month-old.
    Vet Hum Toxicol 1995 Dec;37(6):557-8

    Zusammenfassung in engl. Sprache:
    Ingestion of significant quantities of Melaleuca oil or Australian tea tree oil has been described only once in the medical literature. This report describes a 17-mo-old male who ingested less than 10 ml of the oil and developed ataxia and drowsiness. Emergency physicians, poison control personnel and pediatricians should be aware of potential toxicity from this product.

    (10) Knight TE, Hausen BM
    Melaleuca oil (tea tree oil) dermatitis.
    J Am Acad Dermatol 1994 Mar;30(3):423-7

    (11) Woolf A
    Essential oil poisoning.
    J Toxicol Clin Toxicol 1999;37(6):721-7

    (12) Moss A
    Tea tree oil poisioning
    Med J Aust 1994 Feb 21;160(4):236

    (13)Rubel DM Freeman S, Southwell IA
    Tea tree oil allergy: what is the offending agent? Report of three of cases tea tree oil allergy and review of the literature.
    Australas J Dermatol 1998 Nov;39(4):244-7

    Zusammenfassung in engl. Sprache:
    Tea tree oil is currently enjoying popularity as a 'cure-all' for a variety of skin conditions, from infections to psoriasis, and many household and personal products containing Melaleuca oil are available. However, despite its chemical complexities and enthusiastic use, there have been only a few reports of allergic reactions to tea tree oil. At the Skin and Cancer Foundation (Sydney, NSW, Australia), three of 28 normal volunteers tested strongly positive to patch testing with tea tree oil. Following further patch testing with tea tree oil constituents, all three patients reacted strongly to two preparations containing sesquiterpenoid fractions of the oil. Because patients often neglect to mention that they have used 'natural' remedies, it is important that physicians are aware of the potential adverse effects of these products. Furthermore, identification of the allergenic ingredients in tea tree oil may assist the growing industry to produce safer products.

    (14) COD, Allergen wirken Inhaltsstoffe wie Terpine und Terpinole -
    Wann Teebaumöl aus Gesichtspickeln eine Kontaktdermatitis macht
    Ärzte Zeitung vom 7.4.1998
    http://www.aerztezeitung.de/de/htm/net/allergie/065a0102.htm

    2) Aromatherapie und Ihre Katze (Auzug in engl. Sprache)
    Aromatherapy? No, we're not talking about lighting candles and simmering potpourri for your kitty! Classically, aromatherapy is the therapeutic use of essential oils. Essential oils are extracted from the flowers, leaves, stems, roots, seeds and bark of many different plants, and while their most obvious property is that they are aromatic, it is these "oils" which act as the plant's immune system- fighting off bacteria, viruses, yeasts, molds, and other insects.

    But there's a big problem here- and that is that cats cannot tolerate or metabolize essential oils. Their use can lead to symptoms of toxicity or even death. Why can cats not tolerate the oils? There are several reasons. The major one is that they cannot metabolize them the way that dogs or humans can. (they also cannot metabolize certain herbs or allopathic meds, either) This means that they are not efficiently excreted by the body and can build up to toxic levels.

    Symptoms of toxicity include vomiting, dizziness, clumsiness, lack of appetite and lack of energy. The next one is that cats have very thin, delicate skin. This means that essential oils can be absorbed more rapidly into their skin and enter the bloodstream. Cats also dislike strong odors and generally keep away from strong scents- even highly diluted essential oils.

    I have run into several instances where cat owners almost killed their cats even by using just one drop of essential oil on their paws or belly, or diffusing them in the area where the litter box was located. Neither the owners or the vets knew what had happened- they just thought it to be a "mystery poisoning" which could not be detected. Luckily, their cats spent several days at the vet receiving fluids, and did not suffer any permanent health problems as a result. I am sure that many instances such as this happen every day, as there are many cat products out there which do contain essential oils. Shampoos, coat sprays, ear cleaners, rechargeable flea collars and herbal dips. Many companies refer to essential oils as "oil" (as in "Clove oil") or "herbal oils". Please read labels carefully and pass on the word about the potential dangers of essential oils for cats- too many people are unaware of the dangers.

    3) Teebaumöl - toxisch für Katzen (in engl. Sprache)
    TEA TREE OIL - TOXIC TO CATS
    Copyright 1995, 1999 Sarah Hartwell

    Tea Tree oil (oil of Melaleuca alternifolia, Oleum Melaleucae) is often promoted as pretty much the best thing since flu jabs as far as cats are concerned. It is a colourless or pale yellow oil obtained by steam distillation of the freshly harvested leaves of Melaleuca alternifolia (Australian Tea Tree). The main active ingredients are cyclic terpenes.

    Tea Tree oil is promoted for the treatment of many skin problems and to control external parasites. Tea Tree oil lotions, shampoos and wipes are readily available from pet stores. It has been tested on humans and has been found to be effective on larger animals such as horses and sheep. In humans, it has been used in dentistry. However, animals and humans have been poisoned (sometimes fatally) from topical use or accidental ingestion of tea tree oil. Use of tea tree oil to control fleas has resulted in the death of kittens.

    Claims For Tea Tree Oil
    The oil is reputed to have mild antibacterial and antifungal properties and is marketed as a natural remedy in veterinary and human medicine. It has proven antiseptic, antibacterial and fungicidal properties. It is sold in cat skin-care products for cleaning, healing, soothing and relieving itching associated with allergies, insect bites, hotspots, burns, abrasions, minor rashes and irritations. It is claimed that Tea Tree oil is an effective deodorizer, fur detangler, external parasite repellent and that it restores lustre to fur. It is actively promoted for its ability to penetrate the skin. The oil is highly lipophilic (attracted to fats, solvent) and is rapidly absorbed through intact skin (even faster through open wounds). It may also be ingested or absorbed orally through mucous membranes when a cat self-grooms.

    Many cat owners claim to use Tea Tree oil without any adverse effect, however, there have been reports from the US that Tea Tree oil is toxic, to cats. There are unconfirmed reports of cats which have died following the its use. In the US, cat owners are advised to seek the advice of a vet before using the oil on cats. A Californian producer of the oil was reportedly unhappy about its Tea Tree product being promoted for use on cats due to concerns over its potential toxicity. In the UK there appears to be no mention of possible ill-effects or contra-indications and little awareness of its toxicity.

    An American expert in the use of essential oils (who has used Tea Tree oil successfully to treat skin infections in cats) recommends that the oil should not be used where the cat can lick it off, This addresses the hazard of ingestion, but not of absorption through the skin or through wounds (such as unhealed flea bites).

    Cases of Tea Tree Oil Poisoning
    In the early 1990s, it was suggested that cats with nerve disorders were unable to tolerate Tea Tree oil and suffered ill effects from its use. It was recommended that the amount of the oil in a product such as a cat shampoo should not exceed 1% although even that small amount may be toxic to certain individuals. American cat owners were advised not to use Tea Tree oil at all on cats with diabetes, epilepsy, metabolic or neurological disorders or on young kittens whose immature livers may not be able to cope with it.

    Cases of Tea Tree oil poisoning have since been reported to the National Animal Poison Control Center (NAPCC) of the US following external application of the oil to cats. In most cases, the oil had been used at inappropriately high doses, causing acute poisoning. Symptoms occurred 2 - 8 hours after topical application of Tea Tree oil products. Symptoms were depression, weakness, ataxia, lack of coordination, behavioural disorders and muscle tremors. Warning signs may include vomiting, dizziness, clumsiness, lack of appetite and lack of energy.

    Treatment is by removing residual amounts of oil from the skin by bathing the cat in a non-insecticidal shampoo. Intravenous fluids and glucose may were sometimes required to strengthen the animal, to overcome hypotension and to aid renal elimination (elimination in the urine). Where the oil had been ingested (licked off through grooming) activated charcoal and a cathartic was required to decrease the amount of oil absorbed in the gut. It has been reported that cats treated for Tea Tree oil poisoning recovered within 2-3 days following treatment of clinical signs and supportive care.

    There is no specific antidote for the adverse reactions caused by dermal (skin) overexposure to Tea Tree oil (or related essential oils). Basic supportive care is required, including monitoring of respiratory and cardiovascular functions, checking for possible hypothermia and providing additional warmth if needed.

    Toxic Components of Tea Tree Oil
    Tea Tree oil (melaleuca, Melaleuca alternifolia) is a phenol-containing essential oil. Its active ingredients are cyclic terpenes which have a similar structure and action to turpentine (a known toxin) - in fact Tea Trea oil makes a good paint solvent! Cats are uniquely sensitive to phenolics and other benzene-based compounds. Benzyl alcohol (a preservative) is toxic to cats.

    The acute toxicity for the major terpenic compounds (linalool, ocimene, alpha-terpinene, 1,8-cineole, terpinolene, camphene) is 2 - 5 g/kg body weight, which is considered a moderately toxic range. From a toxicologic point of view Tea Tree oil is comparable to oil of turpentine, which is readily absorbed from the gastrointestinal tract and skin. In addition, cats have relatively thin, delicate skin and Tea Tree oil is highly lipophilic (attracted to fats, solvent). This means that the oil is absorbed rapidly and enters the bloodstream. These factors may account for the poisoning cases reported to the NAPCC.

    Mean Percentage Composition of Major Components of Tea Tree Oil, Terpinen-4-ol Type (the low cineole oil specified by the Standards Association of Australia)
    *97 components have been identified, this table relates to major components only.

    Component*

    Mean
    Percentage

    Component*

    Mean
    Percentage

    a-pinene

    2.46

    g-terpinene

    20.20

    a-thujene

    0.83

    r-cymene

    2.80

    beta-pinene

    0.66

    terpinolene

    3.45

    sabinene

    0.45

    aromadendrene

    1.68

    myrcene

    0.86

    terpinen-4-ol

    37.93

    a-phellandrene

    0.44

    virdiflorene

    1.68

    a-terpinene

    9.56

    a-terpineol

    3.01

    limonene

    1.01

    d-cadinene

    1.49

    beta-phellandrene

    0.94

    globulol

    0.86

    1,8-cineole

    3.87

    virdiflorol

    0.33



    Cats are notoriously sensitive to toxins; their livers are not able to metabolize many substances which may safely be used on dogs (cats have been poisoned through use of dog flea preparations). For this reason, a substance shown to be beneficial and safe for humans may be unsuitable for use on cats. e.g. to cover the area where oil is applied.

    Cats cannot efficiently metabolize substances present in certain essential oils (including Tea Tree oil), which will therefore build up in the cat's body. This means that they are not efficiently excreted by the body and can accumulate in soft tissues and vital organs. Over a period of time, the substances can reach toxic levels which cause death or symptoms of poisoning. An owner could therefore use Tea Tree oil in supposedly safe low concentrations for some time with no symptoms, though the cat is being slowly poisoned as the toxins accumulate. This is similar to they way that heavy metals (e.g. lead, zinc) or poly-chlorinated bi-phenols (PCBs) accumulate in the soft tissues and organs. An added danger is that cheap essential oils may be adulterated with other things for various reasons; the combination of substances could be more toxic than the unadulterated oil.

    The other effects of long term use of Tea Tree oil on cats are not known, especially any carcinogenic (cancer-forming) effects. Nor is it confirmed whether it reacts with prescription medications or non-prescription items such as flea-treatments (sprays, powders and especially long-acting treatments added to the food or applied in absorbable form to the back of the neck). It is therefore recommended that Tea Tree oil is not used within days, possibly weeks, of other treatments.

    Irresponsible Marketing of Tea Tree Oil
    I contacted a distributor of Tea Tree oil products in the UK with specific reference to potential toxicity of the oil (based on US studies). The company provided an information leaflet and although the oil appears useful in treating skin conditions and ecto-parasites (fleas, lice, mites etc) there is no scientific qualification for its effectiveness. The leaflet carried the following qualification:

    "The statements made herein are for information purposes only. Many statements and claims made herein are not based on clinical data but are founded on anecdotal data that cannot be quoted on products for sale in the marketplace. This document is not presented as a scientific paper."

    It is worrying that a product is marketed for safe use on cats on the basis of anecdotal information related to humans, sheep and horses with no consideration given to the cat's poor ability to metabolize substances harmless to other species. It is of concern that the statements and claims made for the product are scientifically unproven. Herbal remedies used safely on humans for hundreds of years may be unsuitable for felines due to their different metabolism.

    The leaflet claimed that the "absence of toxicity" and "general perfect tolerance" are attributes of Tea Tree oil. This conflicts with American reports and instances of poisoning reported to NAPCC. The leaflet also contained a list of Tea Tree oil constituents: alpha-terpinene, gamma-terpinene, cymene, alpha-terpineol, sesquiterpenes and up to 10% of cineole (British Pharmaceutical Codex, 1949). High levels of cineole may irritate mucous membranes, so low cineole oil is used for medicinal purposes.

    Although the leaflet contained references to in vitro and in vivo studies, these were related to the oil's antimicrobial properties, not to its toxicity. The cat was not specifically mentioned. The idea of toxicology tests e.g. LD50 - lethal dosage - tests on cats will be abhorrent to cat owners, although the oil could be tested on feline cell cultures.

    Results of tests on humans do not prove that a product is suitable for cats since cats are very poor at metabolising toxic substances. For example, Aspirin is a useful painkiller in humans and well tolerated by most people, but it is highly toxic to cats. Since tea Tree oil can penetrate the skin and be ingested when a cat self-grooms, there is a possibility of it accumulating in the cat's liver and building up to toxic levels.

    The UK distributors' leaflet presented only favourable information. It did not address the toxicity problem of Tea Tree oil or list the contra-indications if it is used. There was also no indication of whether the concentration of oil in the products was above the 1% 'safe' threshold recommended at the time the leaflet was issued. The distributors failed to explain why Tea Tree oil is promoted as safe and non-toxic in the UK but is considered toxic in the US. This is a case of irresponsible marketing and may already have led to 'mystery poisonings' or even deaths in cats and kittens.

    Other Essential Oils
    For the sake of completeness, Tea Tree oil is not the only commonly found essential oil. Herbal remedies contain a variety of oils, a number of which are dangerous to cats. Problems commonly occur when an oil safe for use on humans or dogs are used on cats. Incorrect usage of an oil is almost guaranteed to cause problems. Problems also occur when an oil is 'in fashion' an marketed using anecdotal evidence; its effects on cats may not have been researched properly. Tea Tree oil is currently a fashionable remedy.

    There have been cases of poisoning resulting from a single drop of an essential oil (not only Tea Tree oil, though this is the one most readily available to most cat owners) on their paws or belly, or diffusing them in the area where the litter box was located. Often the reaction was considered a "mystery poisoning" and the toxic agent was not readily identified. Many cat products now contain Tea Tree oil: shampoos, coat sprays, 'antiseptic' wipes, ear cleaners, rechargeable flea collars and herbal dips. Some are simply labelled as "herbal oils".

    Essential oils which contain phenols are particularly toxic to cats and cause liver damage. These include Oregano, Thyme, Eucalyptus, Clove, Cinnamon, Bay Leaf, Parsley and Savory

    Essential oils which contain ketones cause neurological symptoms. These include: Cedar Leaf*, Sage*, Hyssop*, Cyprus*, Lavender, Eucalyptus, Mint ,Caraway*, Citronella ,Clove*, Ginger*, Chamomile, Thyme and Rosemary (those marked * give particular cause for concern).

    Hydrosols and Aromatherapy
    It is recommended that the oil is never be administered orally or used on the skin (cats will lick it off). It isn't known whether Tea Tree oil is safe for use by aromatherapy by nebulization, but it is recommended that it only be used in well-ventilated areas and that the cat be able to leave the room easily if it wishes (cats dislike strong odours).

    For aromatherapy purposes, there is an alternative to the oil which is believed to be safe. A by-product of essential oil production is "hydrosol" (or "hydrolat"). Hydrosols are left behind after the essential oils are steam-distilled from plant matter. Steam is used to extract the essential oil from plant matter. The oil (containing the toxins) is condensed and removed, leaving the steam itself. The steam contains water-soluble plant compounds and can be condensed to form the hydrosol.

    Classically, aromatherapy is the therapeutic use of essential oils. For purposes of aromatherapy for cats, hydrosols are considered safe for use on the skin because they don't contain the actual oil. They are delicately scented and have strong anti-inflammatory properties due to high levels of carboxylic acids. They are also soothing and act as gentle antiseptics. They are also believed to work on the emotions in the same way as Bach Remedies. It is important to locate a manufacturer who does not add essential oil to hydrosols to make it stronger smelling or more potent.

    References:
    Knight, M.J. & Villar, David. Toxicity of melaleuca oil and related essential oils applied topically on dogs and cats. Vet Human Toxicol 36(2): April 1994, p139-142.

    Florida Veterinary Scene Newsletter, 4(5), May/June 1995.

    Promotional leaflet from Pet & Garden Manufacturing plc (Scotland), 1995

    4) Weitere Literaturstellen:
  • Apted JH
    Contact dermatitis associated with the use of tea-tree oil.
    Australas J Dermatol 1991;32(3):177

  • Bhushan M, Beck MH
    Allergic contact dermatitis from tea tree oil in a wart paint.
    Dermatology Centre, Hope Hospital, Salford, Lancs, UK.
    Contact Dermatitis 1997 Feb;36(2):117-8
  • Bruynzeel DP
    Contact dermatitis due to tea tree oil.
    Trop Med Int Health 1999 Sep;4(9):630

  • Carson CF, Riley TV
    Toxicity of the essential oil of Melaleuca alternifolia or tea tree oil.
    J Toxicol Clin Toxicol 1995;33(2):193-4

  • De Groot AC
    Airborne allergic contact dermatitis from tea tree oil.
    Department of Dermatology, Carolus-Liduina Hospital, Hertogenbosch, The Netherlands.
    Contact Dermatitis 1996 Nov;35(5):304-5

  • De Groot AC, Weyland JW
    Systemic contact dermatitis from tea tree oil.
    Department of Dermatology, Carolus Hospital, 's-Hertogenbosch, The Netherlands.
    Contact Dermatitis 1992 Oct;27(4):279-80
  • Hackzell-Bradley M, Bradley T, Fischer T
    A case report. Contact allergy caused by tea tree oil
    Hudkliniken och Allergicentrum, Karolinska sjukhuset, Solna.
    Lakartidningen 1997 Nov 19;94(47):4359-61

  • Hausen BM; ReichlingJ; Harkenthal M
    Degradation products of monoterpenes are the sensitizing agents in tea tree oil
    Dermatologisches Zentrum Buxtehude und Institut fr Pharmazeutische Biologie, Heidelberg, Germany
    AM.J. Contact Dermat.; VOL 10, ISS 2, 1999, P 68 - 77

  • Khanna M, Qasem K, Sasseville D
    Allergic contact dermatitis to tea tree oil with erythema multiforme-like ID reaction.

    The commercial production of tea tree oil, extracted from Melaleuca alternifolia Cheel, has considerably increased over the past 15 years in response to a strong demand for natural remedies and aromatic substances. The number of case reports that describe allergic contact dermatitis (ACD) to this essential oil is also on the rise. We report an additional case of ACD to tea tree oil that presented with an extensive erythema multiforme-like reaction. A skin biopsy was performed from a targetlike lesion distant from the site of the initial dermatitis. The patient was treated with systemic and topical corticosteroids. Five months later, he was patch tested to the North American standard series, to his own tea tree oil, to a fresh batch of tea tree oil, and to some related allergens. The skin biopsy showed a spongiotic dermatitis without histological features of erythema multiforme. Patch testing elicited a 3+ reaction to old, oxidized tea tree oil, a 2+ reaction to fresh tea tree oil, a 2+ reaction to colophony, a 1+ reaction to abitol, and a 1+ reaction to balsam of Peru. We believe this is the first report of erythema multiforme-like reaction secondary to ACD from tea tree oil. Other interesting features are the stronger reaction to oxidized than to fresh tea tree oil, and concomitant reactivity to colophony, abitol, and balsam of Peru.
    Copyright 2000 by W.B. Saunders Company
    Division of Dermatology, McGill University Health Center, Royal Victoria Hospital, Montreal, Quebec, Canada.
    Am J Contact Dermat 2000 Dec;11(4):238-42

  • Kranke B
    Allergy-inducing potency of tea tree oil
    Universitaets-Hautklinik, Abteilung fur Umweltdermatologie, Graz.
    Hautarzt 1997 Mar;48(3):203-4

  • Selvaag E; Eriksen B; Thune P
    Contact allery due to tea tree oil and cross-sensitization to colophony.
    Contact Dermatitis; 31(2), 1994, P 124 - 125.
    Soderberg TA; Johansson A; Gref R

    Toxic effects of some conifer resinacids and tea tree oil on human epithelial and fibroblast cells.
    Department of Clinical Bacteriology, Pathology and Nutritional Research; University of Uppsala, Sweden.
    Toxicology; VOL 107, ISS 2, 1996, P99-109

  • van der Valk PG, de Groot AC, Bruynzeel DP, Coenraads PJ, Weijland JW
    Allergic contact eczema due to 'tea tree' oil
    In four patients, three women aged 45, 29 and 52 years and a man aged 45 years, allergic contact dermatitis due to 'tea tree' oil was diagnosed. The case of the man was published before. 'Tea tree' oils are essential oils distilled from the leaves of myrtaceous trees and shrubs occurring in Australia and South-East Asia. The 'tea tree' oil available in the Netherlands is distilled from the Melaleuca alternifolia and mainly contains eucalyptol. Eucalyptol is probably the most important allergen.
    Academisch Ziekenhuis, afd. Dermatologie, Nijmegen.
    Ned Tijdschr Geneeskd 1994 Apr 16;138(16):823-5

  • Varma S, Blackford S, Statham BN, Blackwell A
    Combined contact allergy to tea tree oil and lavender oil complicating chronic vulvovaginitis.
    Department of Dermatology, University Hospital of Wales, Cardiff, UK.
    Contact Dermatitis 2000 May;42(5):309-10
    Zhang SY, Robertson D
    A study of tea tree oil ototoxicity.
    Tea tree oil shows promise as an effective treatment for a number of micro-organisms commonly associated with otitis externa and otitis media, but its possible ototoxicity has not been previously assessed. The ototoxicity of tea tree oil was examined in the guinea pig by measuring the thresholds of the compound auditory nerve action potential (CAP) to tone bursts before and after instillation of the oil into the middle ear. After 30 min of instillation, 100% tea tree oil caused a partial CAP threshold elevation at 20 kHz. A lower concentration of oil [2% tea tree oil dissolved in saline using 0.5% detergent (Tween-80)] did not cause any significant lasting threshold change after middle ear instillation for the same period of time. The latter concentration of oil is greater than the minimum inhibitory concentration reported for most micro-organisms in the effective spectrum of the oil and this suggests that this concentration may be safe and effective provided only short exposures (about 30 min) are used. The results suggest that high concentrations of tea tree oil applied to the round window for a relatively short time are to some extent ototoxic to the high-frequency region of the cochlea. Hence further study is needed to establish whether tea tree oil can be used with safety in the treatment of external and middle ear infections. Copyright 2000 S. Karger AG, Basel.
    Auditory Laboratory, Department of Physiology, University of Western Australia, Nedlands, Australia.
    Audiol Neurootol 2000 Mar-Apr;5(2):64-8



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    mit freundlicher Genehmigung der Kollegin
    Dr. med. vet. Petra Sindern, Neu Wulmstorf