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Different plants can cause skin sensitization such as quinones, Mansonia Altissima (African black walnut), Tectona grandis (teak). Occupational plant dermatitis occurs in gardeners, forest workers and others.

Children are exposed to plant dermatitis during playing outdoors or indoors from roses, shady plants and even dried leaves and flowers kept in houses as part of the decorations.

Internal or external plantations, grass, shrubs can cause skin sensitization or exacerbation the existing eczema in children.

Poison ivy (Rhus toxicodendron) and poison oak, cashew nut, mango fruit, lacquers from the Japanese lacquer tree and Cedar may act also as sensitizers.

The sensitizer in beeswax derived from poplar resin (propolis), in which a cinnamic acid ester may be the major allergen .

Balsam of Peru, balsam of pine may cause skin sensitization .

A major allergen in garlic is diallyldisulphide .

Clinical features of plant dermatitis

The clinical picture and the severity of the reaction depends to a great extent on the patient‘s susceptibility, site of skin coming in contact with the allergen and the concentration of the sensitizer in the plants. Delicate skin of children and intertriginous areas are more susceptible to severe reaction. Bullous reaction is not uncommon in children.

Skin manifestations of plant dermatitis begins as erythematous reaction of different shapes and may take the shape of the leaf or the flower to which the skin was exposed. Urticarial, Vesiculo-bullous and even bullae may be formed at the site of contact. The skin may become abraded and weeping due to rupture of the bullae and vesicles.Secondary bacterial infection may complicate the abraded skin surface.

Systemic manifestations such as hay fever, rhinitis and asthma may occur in atopic patients.

Some types of plants such as figs may cause photosensitization, where the eczematous reaction appears mainly on the sun exposed areas after exposure to sunlight causing erythema, polymorphous light eruption and even bullous reactions and hyperpigmentation.

Fig.190. Hyperpigmentation( Photosensetization byFurocumarine in figs trees)

Diagnosis of plant dermatitis

Patch test may detect the sensitizer. It should be noted that false positive reaction is common. Usually one centimeter is taken from the leaf and is used for patch testing.

Some type of plant dermatitis has seasonal variations, which appears in the same time each year. This may be of help in spotting the blamed plant, flower or grasses.

Other new different tests may be used to diagnose the causative allergen. False positive and negative reactions may also occurs.

Treatment of plant dermatitis

Avoid exposure to the specific plant that may cause dermatitis.

Acute dermatitis with oozing lesions: using drying lotions such as potassium permanganate 1:9000  compresses and topical corticosteroids cream or in combination with antibacterial preparation if there is secondary bacterial infections.

Systemic corticosteroids are kept for severe cases especially complicated with severe systemic manifestations. If systemic steroids are indicated, Depot medrol injection is preferred.

Anti-histamines are indicated to relieve itching.

Antibacterial preparations are needed to combat secondary bacterial infections.

Desensitization against the specific sensitizer may help few patients.Care should be taken into consideration during skin sensitization especially in hyper allergic individuals. Mild preparation is used first .The patient should be kept under observation after giving the injection .Antishock measures and oxygen should be kept always at hand. Skin sensitization is given mainly to adults. Infants and young children are better excluded from desensitization therapy.



This type of dermatitis is common in children playing in the green area of houses, courts and football courts covered by grass. Dermatitis may develop within the first twenty-four hours on areas coming in contact with grass.                                                                                 

Patch test for grass is positive.



Different plant products may cause skin sensitization.

  1. Essential oils: present in the peel of citrus fruits, the leaves of eucalyptus tree and the park of cinnamon tree.

  2. Cinnamon oil: used as flavoring agent in lipsticks, chewing gums, toothpastes and in pastry bakeries.

  3. Clove oil, euogenol are used by dentists.

  4. Lemon oil: present in lemon tree and lemon peel.

  5. Balsam of Peru: contains essential oil, which may cause contact dermatitis.

  6. Vanilla: this is extracted from vanilla plant. It is used as a flavoring agent in different foodstuffs such as ice creams, cakes, gums and many others. Vanilla may cause contact dermatitis to the skin or mucous membranes.

  7. Furocoumarines present in certain plants such as figs, dill, celery, lime, mustard, meadow grass and parsnip may cause photosensitization. Erythema, vesicular and bullous reaction may appear at the areas coming in contact with these substances. The reaction appears after exposure of the area previously in contact with the photosensitizer to sunlight.

  8. Pollens
    Some types of eczema show seasonal variations flaring up in certain months of the year as in the season of pollens or during winter, causing skin sensitization. The skin lesion is mainly on the neck, face, hands and the legs. Other manifestations such as asthma, urticaria and hay fever may occur.

  9. Plants and woods:
    Citrus peel, flower bulbs, garlic, roses, grass, wood dust, spices, corn, onion, pineapple and the mustard family can act as irritants, and some can cause bullous skin reactions.

Pesticide dermatitis

These include fungicides, rodenticides and herbicides.

Thiuram sulfides, thiocarbamates, formaldehyde, nitrofurazone,

Organic mercury compounds, hexachlorocyclohexane (lindane) and pyrethrum are the most common sensitizing pesticides.

Organophosphorus pesticides have occasionally been reported as sensitizers.



The epoxy resins are among the most sensitizing substances which have been introduced in industrial work in recent years. They are used for electric insulation for coating, or casting with fiberglass .

These are also used in laminating of metals, coating metals, flooring and filling defects in cement .

They are efficient glues for metals, rubber, polyester resins and ceramics, cardiac pacemakers and hypodermic needles .

Fig. 191a. Epoxy resin dermatitis

Epoxy resins used in the manufacture of plastic as plastic handbags, gloves , glues and paints . Resins are used in polyester fibers as Dacron or polyester films may be used in the manufacture of diapers may act as sensitizers causing dermatitis.



Rhus dermatitis is a plant dermatitis, which results from contact of the skin with poison ivy, poison oak and poison sumac. The clinical manifestations appear immediately after exposure or may take longer time to manifest.

Skin lesions present with severe pruritus at the site of contact with an erythematous, edematous area. Vesicles and bullae may develop which are usually linear or grouped. The  most common sites involved are the uncovered areas of the body such as face, extremities and areas covered by light clothing. The eyelids and lips may become edematous leading in severe allergic reactions to complete closure of the eyelids.

Fig.191b. Rhus dermatitis

The arrangement of the vesicles in a linear shape is usually diagnostic for rhus dermatitis.

Other types of dermatitis related to rhus are lacquer dermatitis, which is caused by furniture lacquer, Cashew wood, paint, synthetic glue, varnish, ginkgolic acid, which is available in Ginkgo tree.

Dermatitis may also develop from certain flowers such as prime rose, philodendron, English ivy,Chrysanthemum flowers and the Prairie flowers. These types may cause severe dermatitis and that is why allergic children should be kept away from contact with such flowers and plants.

Indoor plantation and shade plants may cause also dermatitis.

Cedar trees, pine, mahogany, teak, rubber trees and figs may cause also dermatitis.

Pollen dermatitis from pollens in ragweed which occurs during ragweed pollination which is usually after summer time due to the ragweed oil which causes contact dermatitis, asthma and hay fever.

Vegetables such as garlic, onion, tomato, asparagus, cocumber, parsley and celery can cause contact dermatitis.

Ink extracted from oleoresin may cause dermatitis especially in children. Laundry marking ink dermatitis may occur when the ink, is used for marking clothes in laundry and stores.



Seaweeds in oceans or different water sources may cause contact dermatitis to the part of skin exposed to weeds such the blue-green alga. Green alga may be present in stagnant pool water. Pruritus and severe skin reaction may develop after contact with these water plants. The commonest sites affected are the areas covered by the bathing suits. Erythematous, vesicular and desquamativa lesions may develop.

Skin patch test with alga is strongly positive.


Skin tests may be reliable to detect the specific sensitizer.


  1. Sensitive patients should avoid exposure to plants containing the sensitizer.

  2. Treatment of affected individuals includes thorough washing of clothing to remove any resins in the clothes.

  3. The patient should take a shower to remove any resin on the skin surface.

  4. Mild steroid cream can be applied. Cold milk compresses are also helpful.

  5. Corticosteroid, orally or IM injection (Depot medrol, 40 mg.) may be required in severe and widespread lesions.

  6. Antihistamines are used to relieve itching.

  7. Bulla may be opened and potassium permanganate 1:9000 compresses can be used.

  8. Desensitization.



  1. Kligman AM. Poison ivy (Rhus) dermatitis. Arch Dermatol 1958; 77: 149-80.

  2. Malten KE. Tracing back a positive to epoxy resins. Contact Derm 1977; 3: 217.

  3. Malten KE. Tracing back a positive to epoxy resins. Contact Derm 1977; 3: 217.

  4. Holst R, Kirby J, Magnusson B. Sensitization to tropical woods giving erythema multiforme-like eruphons. Contact Derm 1976; 2: 295

  5. Woods B. Irritant plants. Trans St John‘s Hosp Dermatol Soc 1962; 48: 75-82.

  6. Maibach HI, Epstein WL. Plant dermatitis: fact and fancy. Postgrad Med 1964; 35: 571-4.

  7. Mitchell JC, Dupuis G, Geissman TA. Allergic contact dermatitis from sesquiterpenoids of plants. Br J Dermatol 1972; 87: 235-40.

  8. Mitchell JC, Geissmann TA, Dupuis G et al. Allergic contact dermatitis caused by Artemisia and Chrysanthemum species. JInvest Dermatol 1971; 56: 98-101.

  9. Mitchell JC, Rook AJ. Diagnosis of contact dermatitis from plants. Int J Dermatol 1977; 16: 257-66.

  10. Rothenborg HW, Menne T, St3/4lin K-E. Temperature dependent primary irritant dermatitis from lemon perfume. Contact Derm 1977; 3: 37-48.

  11. Maibach HI, Epstein WL. Plant dermatitis: fact and fancy. Postgrad Med 1964; 35: 571-4.

  12. Mitchell JC, Dupuis G, Geissman TA. Allergic contact dermatitis from sesquiterpenoids of plants. Br J Dermatol 1972; 87: 235-40.

  13. Mitchell JC, Geissmann TA, Dupuis G et al. Allergic contact dermatitis caused by Artemisia and Chrysanthemum species. J Invest Dermatol 1971; 56: 98-101.

  14. Powell SM, Barrett DK. An outbreak of contact dermatitis from Rhus verniciflua (Toxicondendron vernifluvum). Contact Derm 1986; 14: 288-9.

  15. Rook A. Plant dermatitis. Br Med J 1960; 2: 1771-4.
    Rudzki E, Grzywa A. Immediate reactions to Balsam of Peru, cassia oil and ethyl vanillin. Contact Derm 1976; 2: 360-1

  16. Thune PO, Solberg YJ. Photosensitivity and allergy to aromatic lichen acids and compositae oleoresins and other plant substances. Contact Derm 1980; 6: 64-71.


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