Hogweed burns are skin lesions resulting from contact with a poisonous plant. After touching the hogweed under the influence of ultraviolet light, itchy erythema appears on the skin, and after a while burn blisters form. When inhaling essential oils, there is a sharp weakness, dizziness, fainting. Burns are diagnosed on the basis of anamnesis and a vivid clinical picture. Assistance in contact with hogweed consists in washing and hiding the skin from sunlight, taking antihistamines and NSAIDs. After opening the blisters, local antiseptics, steroid and wound healing ointments are used.
Burns from contact with hogweed are photochemical dermatitis that develops as a result of the plant’s juice getting on the skin and subsequent UV irradiation.The danger of contact with hogweed is the risk of getting burns of the III degree, severe allergic reaction, toxic poisoning. Cases of deaths among people and animals in contact with the plant have been recorded.
Sosnovsky’s hogweed (Heraculum sosnowskyi) is an umbrella plant reaching 3 m in height. In 1940-1950 it was cultivated as a fodder crop for cattle. However, later its use as a silage plant was abandoned, because the feed from the hogweed worsened the taste qualities of milk and meat, and also caused infertility in cows and the birth of calves with deformities. After the cessation of agricultural cultivation, the hogweed began to grow like weeds in abandoned fields and pastures, wastelands, roadsides.
The greatest danger of hogweed is during the flowering period, which falls on June-July. The juice of the plant contains furanokoumarins – chemicals that are activated under the influence of ultraviolet radiation, causing photodermatoses and chemical burns of the skin. Contact with this dangerous plant occurs during a walk through the thickets, children’s games, mowing grass without sufficient protection of the skin, as a result of accidental touching of leaves with ignorance of its toxic properties.
More often than others, hogweed burns are received by children, farmers, agricultural workers, summer residents. Allergic manifestations develop in persons who have hypersensitivity to essential oils of the plant. Factors aggravating the severity of the lesion are:
- clear sunny weather;
- high humidity;
- duration of contact;
- a large area of contact of the hogweed with the skin;
- intensity of UVI;
- light skin (first phototype);
- allergic mood of the body.
Furocoumarins (furanocoumarins) contained in the juice of the plant play a key role in the mechanism of development of skin burns in contact with hogweed: xanthotoxin, bergapten, angelicin, 5- and 8-methoxypsoralen. Their molecules attach to the pyrimidine bases of the nucleic acids of keratinocytes and melanocytes of the skin. Phototoxicity of furanokoumarins is manifested under the influence of ultraviolet light, therefore bullous dermatitis does not occur immediately after contact with hogweed, but after some time, after sunlight hits the skin.
When UV radiation is absorbed by furocoumarins, photochemical reactions occur in skin cells, which result in the release of reactive oxygen species, a large amount of thermal and light energy, which damages mitochondria and cell membranes, causes cellular apoptosis. These processes lead to the appearance of hyperemia, swelling and blisters on the skin. In the future, the number of melanocytes increases in the affected area, causing the occurrence of protective hyperpigmentation, which protects the skin from further irradiation.
Depending on the severity of clinical manifestations in modern dermatology, there are 3 clinical forms of photodermatitis caused by hogweed:
- Erythematous. It occurs most often, according to the degree of damage corresponds to a thermal burn of the first degree. The main manifestations are represented by burning sensations, skin erythema in the form of stripes and spots. The lesion is limited by the contact area. After about 2 weeks, lamellar peeling of the skin begins, in place of which pigmented spots form.
- Erythematous bullous. The depth of the lesion resembles a grade II burn. Bright hyperemia of the skin is combined with multiple blisters that merge into blisters up to 10 cm in diameter. After a week, crusts form on the site of the sleeping blisters, and later pigmentation. This form of photodermatitis is characterized by moderate intoxication.
- Erosive and ulcerative. The initial manifestations are similar to the erythematous bullous form. After opening the blisters, erosions and deep ulcers form, at the site of healing of which hyperpigmented scars form. Intoxication syndrome is more pronounced.
The first local signs of skin lesions develop a few hours later, or 1-2 days after contact with the plant. At first, there is a clearly defined hyperemia, accompanied by burning, then ‒ small multiple vesicles, which merge into large blisters against the background of increasing swelling of the surrounding tissues. Blisters are thick-walled, tense, sometimes multi-chambered, contain transparent serous exudate. Most often, burns of I-II, less often of III degree develop upon contact with hogweed.
After a few days, spontaneous opening of blisters may occur with the formation of a wound surface or painful erosive and ulcerative defects. Their epithelization occurs slowly with the formation of a scab. In place of the departed crust, post-inflammatory hyperpigmentation is then formed, which can persist for several months.
Most often, the lower legs, forearms and hands are affected, which are in direct contact with the hogweed and are open to sunlight. Atypical localization of burns is observed in childhood. Children often use the stems of the plant for playing, making them into a “spyglass”, a spit tube for darts, a “sword”, a “horse”, etc., therefore, the periorbital and perioral areas, the trunk, the inner surface of the thighs are often affected. The use of plant leaves instead of toilet paper leads to severe burns of the perianal area.
The more pronounced the burns, the brighter the intoxication syndrome: hyperthermia, chills, headache, weakness, lack of appetite. If you inhale essential oils for a long time while staying near the hogweed thickets, severe dizziness and fainting may occur.
Even after complete healing, the skin areas affected by hogweed burns remain sensitive to ultraviolet light, therefore they need protection from sunlight. Deep burns, as well as lesions of the perioral and perianal areas lead to severe scarring of the skin. When the plant comes into contact with the eyes, complete blindness can occur. The course of the wound process can be complicated by suppuration and sepsis. The defeat of hogweed over 80% of the body surface causes fatal consequences.
Patients who have received hogweed burns should be examined by a dermatologist and a combustiologist (in his absence – by a surgeon, traumatologist). Collecting anamnesis helps to make the correct diagnosis. To assess the general condition, clinical and biochemical blood test are performed. The severity of burns is assessed by the depth and area of local lesions.
If it is impossible to collect anamnesis due to the severe general condition of the patient, within the framework of differential diagnosis, it is necessary to exclude other similar skin lesions accompanied by bullous rashes:
- contact dermatitis;
- bullous pemphigoid;
- skin porphyria;
- herpes zoster;
- sun and thermal burns.
Immediately after contact with the hogweed, it is recommended to wash off the juice of the plant from the skin with soap and water or remove it with a wet compress. To avoid the formation of blisters, cover the skin from sunlight with clothing or a gauze bandage, try to stay in the shade for 1-2 weeks. If the eyes are affected, it is necessary to immediately rinse them with water, if the juice gets into the oral cavity, rinse the mouth abundantly. To relieve swelling and itching, taking anti-allergic drugs is necessary. In order to relieve pain and inflammatory syndrome, the use of NSAIDs is permissible.
Treatment of uncomplicated burns
Treatment of local uncomplicated burns with hogweed can be carried out on an outpatient basis, under the supervision of a surgeon. The measures taken depend on the depth and stage of the burn:
At the stage of erythema, cold compresses are used, various stimulators of tissue regeneration in the form of ointments, aerosols, recommended for thermal burns. Topical glucocorticoids are applied to the affected areas to reduce inflammation and swelling of tissues.
With erythematous bullous stage / form of burns from hogweed, it is strictly forbidden to open blisters at home because of the high risk of infection. If there was an opening of the bladder due to negligence, lotions with antiseptics can be applied to the resulting wound surface, and then antibacterial ointments.
At the stage of epithelization, stimulators of dermal regeneration are used again. To prevent rough scarring, you can resort to applying ointments with silver ions.
Treatment of complicated burns
Patients with severe burns from hogweed are hospitalized in a hospital. Perform PHO wounds, necrectomy, bandages using atraumatic wound coverings. In the formation of erosions and ulcerative defects, steroid ointments are used.
Desensitizing therapy is carried out (injections of calcium gluconate, corticosteroids), infusion therapy, in case of infection ‒ antibacterial therapy. The formation of rough scars after a hogweed burn may require delayed autodermoplasty.
Prognosis and prevention
In most cases, after touching the hogweed, burns of the 2nd article develop on the skin, which, with proper care, heal, leaving behind a long pigmentation. Severe burns can occur in children when a large area of the skin surface is affected. A serious danger is the ingestion of borscht juice on the mucous membranes of the eyes, oral cavity, perianal area.
For safety reasons and to avoid burns, it is necessary to bypass the thickets of hogweed, do not touch the plant. When purposefully destroying a weed (mowing, weeding), it is necessary to wear protective clothing covering all parts of the body, protective glasses, a respirator, a headdress, household gloves, rubber boots. It is better to deal with the destruction of hogweed before its flowering, in cloudy weather. After finishing the work, you should take a shower with soap, avoid sun rays on the skin for several days.