Beware The Grey Cocoons On The Wall The Larvae In Them Can Sting

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This is a cocoon of the plaster bagworm larvae, which is typically found on the walls of humid areas in a home. — Wikimedia Commons
Plaster bagworms may be sound unfamiliar to most people, compared to other insects such as mosquitoes, bees and wasps, even though these peculiar pests can be seen strewn over their house walls.
Known scientifically as Phereoeca uterella, this moth species is greyish, flat and roughly half an inch long.
Its cocoon resembles a watermelon or pumpkin seed that sometimes moves.
Some refer to it as a household casebearer, while it is called kamitetep in Malay.
These cocoons, in which the larvae of plaster bagworms live, are made of silk strands, sand, earth and human hair.
They are commonly found in moist, dusty and dark areas of the house, such as in bathrooms, and behind curtains and cupboards.
The larvae will grow and remain in the cocoon, eating mostly spiderwebs and silk fibre, until they become adult plaster bagworms.
Swelling and pain
Plaster bagworms are not only unwelcome pests that look unsightly on house walls, but are also potentially harmful due to the larvae’s stinging ability.
Although the sting may not be as severe as those caused by bees, wasps or bed bugs, it can nonetheless cause skin reactions in the affected areas of the body.
Those who have been stung typically experience prolonged swelling, pain and itching, although the initial sting may have gone unnoticed.
In addition, the sting of the plaster bagworm larvae leaves tiny hairs on the skin that can trigger allergic reactions.
Certain individuals may be susceptible to severe allergy symptoms, such as anaphylaxis.
Anaphylaxis results in the disruption of some of the body’s systems, including a significant decrease in blood pressure, breathing difficulties, loss of consciousness, and eventually death.
The first step after being stung by a plaster bagworm larvae is to carefully remove the hairs that the larvae have left on the skin’s surface.
One effective technique to do so is by sticking adhesive tape on the affected area and pulling it off.
The larvae hairs should come off with the adhesive tape.
Subsequently, the affected area should be cleaned using soap and water.
Cold compresses can also be used to relieve any pain and irritation.
Use a clean cloth, and ice or cold water.
Wrap the ice in the cloth or soak the cloth in cold water for a few minutes.
Apply the cold compress to the affected part for 10-15 minutes.
Do note that applying ice directly onto skin or leaving the cold compress for a longer duration might damage the skin.
Start with self-treatment
Typically, treatment for a sting by plaster bagworm larvae aims to alleviate the symptoms.To prevent plaster bagworms from reproducing, it is essential to apply insecticides and conduct regular cleaning, especially of humid areas in the home. — Dendroica cerulea/Flickr
Generally speaking, the skin reactions resulting from a sting are often mild and can be managed at home.
However, persons experiencing more severe symptoms are advised to seek further assessment at a healthcare facility.
Skin reactions due to the stings can cause irritating aches and pains.
People who have gotten a plaster bagworm sting can use several types of medicines to alleviate the different symptoms.
Painkillers like paracetamol or non-steroidal anti-inflammatory drugs (NSAIDs), e.g. ibuprofen and mefenamic acid, can be taken to relieve pain.
These medicines are available at community pharmacies.
Consumption of these medicines should be done according to the instructed dosage and frequency.
Besides painkillers, topical preparations can also be used in the treatment of plaster bagworm larvae stings if needed.
These topical medicines are applied to the skin of the affected area to reduce itchiness and inflammation.
They can also be obtained at community pharmacies.
Patients are encouraged to seek guidance from the pharmacist on the proper application of these preparations.
Calamine lotion is one topical preparation available over the counter to treat itchiness due to skin irritation.
It is important to shake the lotion bottle well before using it.
The affected individual should apply the lotion to the affected skin area using a cotton ball or similar material.
The lotion should then be left to dry on the skin.
The same step can be repeated as often as needed.
Another topical preparation suitable for reducing inflammation and relieving itchiness is steroid cream.
This should be administered sparingly onto the skin.
It is important to adhere to the specified duration of use, as using any product containing steroids for an extended period of time can result in negative side effects.
Be careful with antihistamines
Medicines from the antihistamine group are also important to reduce allergy symptoms.
Broadly speaking, the body experiences symptoms such as rashes, itching, sneezing and a runny nose as a result of the reactions of histamine in the presence of allergens.
Antihistamines help reduce inflammation in the body by lowering histamine levels.
There are two groups of antihistamines, i.e. first-generation antihistamines and second-generation antihistamines.
These two groups differ in terms of the side effects produced.
First-generation antihistamines, such as chlorpheniramine, diphenhydramine and promethazine, may cause drowsiness and impair alertness.
The risk of such side effects is lower with second-generation antihistamines like loratadine, cetirizine, desloratadine and levocetirizine.
Individuals who are taking first-generation antihistamines are encouraged to stay at home as there is a possibility that they may develop the above-mentioned side effects.
It is best to avoid driving or operating machinery after the consumption of these medicines in order to prevent accidents resulting from drowsiness and lack of concentration.
First-generation antihistamines should also be used with caution for children.
The use of these medicines is not recommended for children younger than two years of age, as these drugs have a risk of causing respiratory distress.
Parents are advised to seek medical advice for appropriate treatment.
Due to the lower probability of developing side effects, those who have been stung by plaster bagworm larvae are strongly advised to take second-generation antihistamines.
Antihistamines are classified as non-prescription controlled medicines that can be acquired from pharmacists at community pharmacies.
The pharmacist can help determine which antihistamines are appropriate according to the individual’s needs.
Clean the house
Typically, skin reactions resulting from plaster bagworm stings tend to resolve naturally within one to two weeks.
Individuals who have gotten a sting should refrain from scratching the affected area, as doing so can cause wounds and increase the risk of infection.
Aside from treating the affected area, plaster bagworm eradication within the house should also be initiated.
To prevent plaster bagworms from reproducing, it is essential to apply insecticides and conduct regular vacuuming, dusting and cleaning of humid areas like the bathroom, closets and beds.
Pest control service providers can also be engaged to help remove the larvae while preventing adult plaster bagworms from reproducing in the house.
Payal Choudhury is a pharmacist at Hospital Tengku Ampuan Najihah, Kuala Pilah, Negri Sembilan. This column is courtesy of the Health Ministry’s Pharmacy Practice and Development Division. For more information, email [email protected]. The information provided is for educational and communication purposes only, and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this article. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
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