What Is Permethrin Cream Used For?
Permethrin cream is primarily used to treat scabies, a highly contagious skin infestation caused by microscopic mites, and sometimes head lice. It works by paralyzing and killing the mites or lice and their eggs.
Understanding Permethrin Cream
Permethrin cream is a widely prescribed topical medication belonging to the pyrethroid family of insecticides. Its effectiveness and relatively low toxicity make it a mainstay in the treatment of certain ectoparasitic infestations. Before delving into its specific applications, it’s crucial to understand its mechanism of action and the conditions it effectively targets.
How Permethrin Cream Works
Permethrin disrupts the nerve cell membranes of insects and mites, leading to paralysis and death. Specifically, it prolongs sodium channel activation, causing continuous depolarization of the nerve cells. This disruption prevents the parasites from functioning normally, ultimately leading to their demise. The cream’s formulation allows for efficient absorption into the parasites’ exoskeletons.
Conditions Treated with Permethrin Cream
Permethrin cream is primarily indicated for the treatment of:
Scabies: This is the most common use. Scabies is characterized by intense itching, particularly at night, and the presence of small, raised bumps or blisters on the skin. Common locations include the webs between fingers, wrists, elbows, armpits, and groin.
Head Lice: While other treatments are often preferred for head lice due to increasing resistance, permethrin cream can be an effective second-line treatment. It kills lice and their eggs (nits).
Proper Application of Permethrin Cream
The effectiveness of permethrin cream hinges on proper application. Here’s a step-by-step guide:
- Preparation: Shower or bathe before applying the cream and dry thoroughly.
- Application: Apply a thin layer of the cream to all areas of the skin from the neck down to the toes. This includes areas that may not appear affected. When treating infants and elderly patients, the cream should also be applied to the scalp, face, and neck, avoiding the eyes, mouth, and mucous membranes.
- Duration: Leave the cream on for 8-14 hours, typically overnight.
- Rinsing: Wash the cream off with soap and water.
- Repetition: Repeat the treatment in 7-14 days, as instructed by your doctor. This is crucial to kill any newly hatched mites.
Common Mistakes to Avoid
- Incomplete Coverage: Failing to apply the cream to all areas of the body.
- Insufficient Duration: Washing the cream off too soon.
- Ignoring Household Contacts: Treating only the affected individual, neglecting close contacts who may also be infected.
- Overuse: Using the cream more frequently than prescribed, which can lead to skin irritation.
Potential Side Effects
While generally well-tolerated, permethrin cream can cause side effects in some individuals. These may include:
- Mild burning or stinging
- Itching
- Redness
- Dryness
Serious side effects are rare, but if you experience severe skin irritation, rash, or allergic reaction, discontinue use and consult a doctor immediately.
Contraindications and Precautions
Permethrin cream is generally safe for most people, but there are certain situations where caution is advised:
- Allergy: Do not use if you are allergic to permethrin or any other pyrethroid insecticides.
- Pregnancy and Breastfeeding: Consult your doctor before using permethrin cream if you are pregnant or breastfeeding. While considered low-risk, it’s essential to weigh the potential benefits against any potential risks.
- Infants: Use with caution in infants under two months of age. Consult a pediatrician before using in this age group.
Resistance to Permethrin
In some areas, resistance to permethrin has been reported, particularly with head lice. If the initial treatment is not effective, alternative medications may be necessary. Your doctor can advise on the best course of action.
Comparing Permethrin to Other Treatments
| Treatment | Condition | Advantages | Disadvantages |
|---|---|---|---|
| Permethrin Cream | Scabies | Effective, readily available, generally well-tolerated | Potential for resistance, requires full-body application |
| Ivermectin (Oral) | Scabies | Convenient (oral), effective in severe cases | Prescription only, not suitable for pregnant women |
| Lindane Lotion | Scabies | Used in the past; less commonly prescribed now. | More toxic than permethrin, risk of seizures |
| Malathion Lotion | Head Lice | Effective against some resistant lice strains | Can be flammable, strong odor |
Frequently Asked Questions (FAQs)
How long does it take for permethrin cream to kill scabies mites?
Permethrin cream begins killing scabies mites upon contact. While the itching may persist for several weeks after treatment due to an allergic reaction to the dead mites and their feces, the active mites are typically killed within a few hours of proper application. It’s important to complete the full course of treatment, including the second application, to ensure complete eradication.
Can I use permethrin cream if I am pregnant or breastfeeding?
It’s crucial to consult your doctor before using permethrin cream if you are pregnant or breastfeeding. While permethrin is considered low-risk during pregnancy and breastfeeding due to minimal absorption, it’s essential to weigh the potential benefits against any potential risks with your healthcare provider.
What should I do if the itching persists after using permethrin cream?
Itching can persist for several weeks after successful treatment with permethrin cream. This is due to an allergic reaction to the dead mites and their waste products. Your doctor may recommend antihistamines or topical corticosteroids to relieve the itching. If the itching is severe or accompanied by new skin lesions, consult your doctor to rule out treatment failure or a secondary infection.
How do I clean my house to prevent re-infestation after using permethrin cream?
To prevent re-infestation, it’s essential to thoroughly clean your home. Wash all bedding, clothing, and towels used in the 3 days prior to treatment in hot water and dry them on high heat. Items that cannot be washed should be dry-cleaned or sealed in a plastic bag for at least 72 hours, and preferably for 2 weeks. Vacuum carpets and upholstery thoroughly.
Can permethrin cream be used on my pets?
Permethrin cream is not intended for use on pets. Some permethrin formulations can be toxic to animals, especially cats. If your pet has a skin condition, consult a veterinarian for appropriate treatment options.
What are the symptoms of scabies?
The hallmark symptom of scabies is intense itching, especially at night. Other symptoms include a rash consisting of small, raised bumps or blisters, typically located between the fingers, wrists, elbows, armpits, groin, and buttocks. The itching may be so intense that it disrupts sleep.
How do I know if I have scabies or something else?
The best way to confirm a diagnosis of scabies is to see a doctor. They can examine your skin and, if necessary, take a skin scraping to look for mites or eggs under a microscope. Other conditions, such as eczema or allergic reactions, can mimic the symptoms of scabies, so a professional diagnosis is essential.
Can I buy permethrin cream over the counter?
Permethrin cream typically requires a prescription from a doctor. While some weaker formulations of pyrethroid insecticides may be available over the counter for other purposes, permethrin cream specifically formulated for scabies treatment is usually prescription-only.
How long is permethrin cream effective after application?
Permethrin cream remains active on the skin for the 8-14 hour duration that it is left on. After rinsing it off, the residual effect is minimal. This is why a repeat application is necessary after 7-14 days, to kill any mites that may have hatched from eggs that survived the initial treatment.
What if I accidentally swallow some permethrin cream?
If you accidentally swallow a small amount of permethrin cream, contact poison control or seek immediate medical attention. Symptoms of permethrin poisoning can include nausea, vomiting, dizziness, and seizures. While serious complications are rare, it’s essential to seek professional medical advice.
Are there any natural alternatives to permethrin cream for scabies?
While some natural remedies are sometimes suggested for scabies, such as tea tree oil or neem oil, there is limited scientific evidence to support their effectiveness. Permethrin cream remains the gold standard treatment, and it’s generally recommended to consult with a doctor before trying alternative therapies.
How do I prevent the spread of scabies?
Preventing the spread of scabies involves several key steps:
- Avoid close contact with individuals who have scabies.
- Wash all bedding, clothing, and towels used in the 3 days prior to treatment in hot water and dry them on high heat.
- Treat all household members and close contacts simultaneously, even if they don’t have symptoms.
- Inform your doctor if you work in a setting where close contact with others is common, such as a daycare center or nursing home.