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Review: Li Yun
It's the season of getting up and relying on courage, driving away the cold and relying on a righteous body.
This weather makes people want to come to the bowl of hot fufu rib yam soup.
As a result, I did not expect that it was because of this whim that the hand of benhua after handling yam was unbearable... It's too hard to cook!
In the past, in the public perception, "plant ingredients" often represented safety and harmlessness, but it is not known that some plant ingredients are not only easy to cause skin problems, but also may be life-threatening when serious.
Today we will talk about the various skin problems caused by the "poisonous" plants in life. (Recommended collection of dry goods throughout the whole process)
Irritating contact dermatitis
Mechanical (physical) stimulation
The taro and konjac commonly found on our table belong to the Tiannanxing family. Note, however, that artificially bred plants are edible, and many wild taro-like plants are inedible.
For example, a kind of potato is a potted plant (folk called dripping guanyin), its juice is poisonous, and every year there are cases of children eating by mistake.
Graph source network
The toxicity of plants in the family Asteraceae is due to the fact that they contain needle-like calcium oxalate crystals, known as needle crystals.
When chewed, needle crystals are released, stinging softer tissues in the mouth and inducing leukocytes to release histamine, allowing other irritating chemicals in the plant to penetrate and aggravate the pain and inflammation of these soft tissues.
Calcium oxalate needle crystals under the microscope
Image source "Deadly Plants"
The reaction triggered by such plants is called mechanically irritating contact dermatitis.
Even some edible plants of the Family Asteraceae are also somewhat toxic, such as contact with raw taro, yam juice will itch the hand is the embodiment of its toxic alkaloids (but less toxic), it is recommended to wear gloves when handling them, thoroughly cooked before eating.
Chemical stimulation
There are also many plants that cause contact dermatitis because of the chemicals they contain that irritate the skin, mouth, or eyes.
This reaction occurs either because these chemicals stimulate special receptors on sensory neurons, or because chemicals bind to proteins on the skin.
Substances capable of triggering chemical irritation of contact dermatitis include, but are not limited to, the following:
1. Capsaicin
A pungent compound that gives chili peppers a "spicy" taste, can cause a burning sensation. When handling peppers, also pay attention not to touch the peppers and rub your eyes, which will cause discomfort and pain in the skin and eyes.
2. Isothiocyanate (source of spicy mustard)
Many cruciferous plants secrete isothiocyanate in the "mustard oil" when they are damaged, which is very irritating. The spicy taste of the mustard we often eat comes from this.
3. Diterpene esters
Found in the white milk of many Euphorbia plants, it is extremely irritating and can cause a strong burning sensation, redness and blistering. People with small children and pets in the family should avoid placing euphorbia potted plants (common poinsettias, etc.) to avoid accidental touch.
4. Protoemite anemone (unsaturated lactone)
Many plants in the family Castoridae cause chemical irritation, such as an ornamental flower, the anemone. When plant tissue is damaged, glycosides are converted into active protoemine, which irritates the skin, causing redness, swelling, and blisters.
Treatment:
The most important of the principles of treatment of irritant contact dermatitis is to avoid contact.
If symptoms are mild, they recover spontaneously after stopping exposure to irritating substances.
If symptoms are severe, or if contact dermatitis is more extensive, systemic steroid medications are required. If there is a secondary infection on the wound, anti-infective therapy is required as soon as possible.
Phytosional solar dermatitis
Some plants are very special, we are exposed to their sap, and they happen to be under ultraviolet light, they can cause skin reactions, this reaction is called plant solar dermatitis.
This is because the furancoumarin contained in phototoxic plant sap, when irradiated with enough ultraviolet light, can react with deoxyribonucleic acid (DNA) in skin cells, leading to cell death and local inflammation.
This kind of skin problem is actually not uncommon, often can see people who have been exposed to photosensitive plants, because of the lack of attention to sun protection, resulting in skin erythema, blisters and pigmentation and so on.
Plants containing furan coumarin that are commonly exposed to are lemons, citrus, celery, mustard greens, carrots and so on.
Case: Peeling lemon + illuminating UV nail lamps cause pigmentation spots
But don't worry too much, plant solar dermatitis is mostly caused by skin contact with photosensitive substances, and is rarely caused by eating. Usually pay attention to washing the juices on your hands in time. (And don't peel oranges in the sun)
If the symptoms are mild, wash the residual juice in time and do a good job of sun protection, and there may be pigmentation formation in the future, but it is generally reversible.
If you accidentally come into contact with plants containing ultra-high amounts of furfuran coumarin, blisters and burns occur, you must seize the time to seek medical treatment.
Contact urticaria
Many species of nettle family, including some large trees, are covered with sting hairs, and the reaction triggered by these stings is called contact urticaria.
When we touch these special stings, the expanded base disc at the base of them is squeezed and the chemicals contained in them are injected into the skin through the hollow hairs. These chemicals are the ones that cause us pain.
After the appearance of contact urticaria, be sure to stop contact with the plant that triggers the reaction, and take antihistamines according to the doctor's instructions, patients who are ineffective against antihistamine drugs need to use glucocorticoids, or even immunosuppressants, and gradually reduce the dose and stop the drug after control.
If you have difficulty breathing or shock, you need to go to the hospital in time for rescue, otherwise your life will be in danger.
Allergic contact dermatitis
There are also some plants that contain mildly sensitizing substances that are prone to rashes, a reaction called allergic contact dermatitis.
Common ones are sumac trees. The allergen of this type of plant, urushiol, is a highly sensitizing substance that triggers allergic reactions by binding to proteins on the skin. The resulting rash can last for weeks or even months.
Image source: yanquecao.com
If the symptoms are limited and not too severe, topical steroid drugs can be used.
If the degree is severe, it is recommended to go to the dermatology department of the hospital as soon as possible.
In general, do not touch the wild plants that you do not know, and please go to the regular vegetable market to buy the plants in the mouth.
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What winter troubles do you have, welcome to leave a message to tell me.
〔References〕
[1] "Deadly Plants" [English] Elizabeth M. A. Dancy, [English] Sonny Larsen
[2] Zhou Yanjun, Xiong Xinchai. A case of irritating contact dermatitis of buttercup[J]. Chinese Journal of Leprosy Dermatology,2020,36(04):234-235.