1/4. Degradation products of monoterpenes are the sensitizing agents in tea tree oil.BACKGROUND: patients using tea tree oil (TTO) topically may become sensitized to this natural remedy. More than 30 cases have been documented in the literature since 1991. OBJECTIVE: Freshly distilled, as well as oxidized TTO, some fractions, and single constituents were used for experimental sensitization in guinea pigs. TTO was stored on a window sill to study the influence of light, oxygen, and warmth. The oxidized oil and different fractions were devoted to experimental sensitization in guinea pigs to determine their sensitizing potency. Fifteen constituents were patch tested in TTO-sensitive patients to find how many may play a role as contact allergens. methods: guinea pigs were sensitized by a modified FCA-method (Freund's complete adjuvant) with freshly distilled TTO, oxidized TTO, the monoterpene and sesquiterpene fraction, and 1, 8-cineole. TTO-sensitive patients were tested with 15 typical constituents and degradation products. Gas chromatographic analysis was used to detect degradation products of the deteriorated TTO. RESULTS: Fresh TTO was revealed to be a very weak sensitizing material whereas oxidized TTO was 3 times stronger. The monoterpene fraction showed to be a stronger sensitizer than the sesquiterpene fraction. All 11 patients reacted mostly with a -plus or even a -plus reaction to alpha-terpinene, terpinolene and ascaridol. alpha-Phellandrene became positive in four patients, myrcene in only two. Gas chromatographic analyses showed that the formation of peroxides increased within 4 days from less than 50 to more than 500 ppm. peroxides, epoxides and endoperoxides were formed. Deterioration products of alpha-terpinene were found to be mainly p-cymene, ascaridol, isoascaridol, a ketoperoxide, and colorless crystals that likely were 1,2,4-trihydroxy menthane. The p-cymene content increased dramatically from 2% to 11.5%. alpha- and gamma-terpinene, as well as terpinolene, were reduced to one half of their former concentration. Ascaridol and isoascaridol have never before been found in TTO. CONCLUSION: tea tree oil kept in open and closed bottles or other containers undergoes photooxidation within a few days to several months, leading to the creation of degradation products that are moderate to strong sensitizers. peroxides, epoxides and endoperoxides, like ascaridol and 1,2,4-trihydroxy menthane, are formed. These must be considered responsible for the development of allergic contact dermatitis seen in individuals treating themselves with the oil. A test series with 15 characteristic constituents is recommended for patch testing.- - - - - - - - - - ranking = 1keywords = tree (Clic here for more details about this article) |
2/4. Generalized lichen nitidus successfully treated with an antituberculous agent.We describe a Japanese girl with generalized lichen nitidus. She had been exposed to mycobacterium tuberculosis at 6 years of age via her teacher. At 8 years of age, she developed severe contact dermatitis on sun-exposed areas after contact with Japanese lacquer trees. Shortly after, numerous tiny, shiny, flesh-coloured papules developed over the upper part of her body. At 10 years of age, she was exposed to a school outbreak of M. tuberculosis. Her eruption showed no response to topical corticosteroids or oral tranilast, but most of the papules completely disappeared after she had received oral isoniazid for 6 months.- - - - - - - - - - ranking = 0.16666666666667keywords = tree (Clic here for more details about this article) |
3/4. Occupational allergic contact dermatitis from lichens in present-day finland.lichens are abundant in forests, living on trees, soil, stones and rocks. They contain usnic acid and other lichen acids that are contact allergens. lichens and liverworts cause woodcutter's dermatitis, eczema that appears in the forest on the bare skin areas, especially in cold and wet weather. Occupational allergic contact dermatitis from lichens occurs in forestry and horticultural workers and in lichen pickers. lichens can cause immediate allergy, contact urticaria, rhinitis and asthma and probably also photoallergic contact dermatitis. lichens are used for the manufacture of oak moss absolute, a fragrance constituent. Oak moss absolute contains lichen acids and is one of the commonest contact allergens. Lichen acid allergy develops either from contact with lichens or from fragrances. We describe 4 cases of occupational allergic contact dermatitis from lichens during the past decade: 2 were farmers and 2 gardeners. 3 of them had allergic reactions to fragrance mix and oak moss absolute. Lichen contact allergy is an old, partly forgotten, syndrome that should be remembered for symptoms in contact with barked wood or wood dust.- - - - - - - - - - ranking = 0.16666666666667keywords = tree (Clic here for more details about this article) |
4/4. Respiratory diseases and food allergy.Both upper and lower respiratory tracts can be affected by food allergy. Manifestations in either may be exclusively due to food allergy (common in infants) or may result from the combined effects of food allergy plus another defect such as gastroesophageal reflux, a congenital defect of the heart or tracheo-bronchial tree, an immunodeficiency syndrome such as isolated IgA or IgG4 deficiency, or a concomitant inhalant allergy. Chronic rhinitis is the most common respiratory tract manifestation of food allergy. When it occurs in conjunction with lung disease, it may be a helpful indicator of activity of the allergic lung disease and of the patient's compliance in following a specific diet. Recurrent serous otitis media may be solely or partially due to food allergy. Large tonsillar and adenoid tissues, sometimes with upper airway obstruction, may be caused, or aggravated by, food allergies. Lower respiratory tract disease manifested by chronic coughing, wheezing, pulmonary infiltrates, or alveolar bleeding may also occur. Lower respiratory tract involvement is generally associated with a greater delay in onset of symptoms and with a larger quantity of allergen ingestion than chronic rhinitis. food allergy should be considered when there is a history of prior intolerance to a food in childhood or of symptoms beginning soon after a particular food was introduced into the diet. It is an important consideration in patients who have chronic respiratory tract disease which does not respond adequately to the usual therapeutic measures and is otherwise unexplained.(ABSTRACT TRUNCATED AT 250 WORDS)- - - - - - - - - - ranking = 0.16666666666667keywords = tree (Clic here for more details about this article) |