Health Tips

The saying ‘seven-year itch’ is typically used to describe a psychological backing that happiness in a marriage or long-term romantic relationship declines after around seven years.

But today, we aren’t going to talk about the seven-year itch in your relationship but in your skin. (we still hope that you maintain a good relationship with your partners though!) It’s called scabies.

What’s scabies?

Scabies is a parasitic and contagious skin disease caused by the mite Sarcoptes scabiei. Here’s how it looks like:

Sarcoptes scabiei. Image credit: DermNetNZ.org via CC BY-NC-ND 3.0 NZ

It’s cute and creepy at the same time, right? Scabies is both endemic and epidemic in countries worldwide, and studies have indicated that scabies are closely associated with poor social and environmental factors, such as poverty and crowded living conditions. In Malaysia, a report published in 1980 stated the prevalence of scabies was 11.6%, and high among children and teenagers, the worst affected being those in the 5-9 years old age group (24%). In another report published in 2010 documented the overall prevalence rate for scabies was 31% among children at welfare homes. 

A person can catch scabies from someone else who has it. The condition spreads easily between people who are in close contact. It is also possible to catch scabies from the clothes of someone with the condition.

Symptoms of scabies

The main symptom of scabies is itching skin, which usually develops within 2 to 6 weeks after infestation of the mites. The itch is generalized, very intense and worst at night.

Besides, people with scabies usually get little red bumps or blisters on their skin. Sometimes the bumps are hard to see. Some people even notice tiny tunnels in their skin where the mites have buried themselves (called scabies burrow). 

Image via Michael Geary, Public domain, via Wikimedia Commons

These are the body parts that are most often affected by scabies:

• Fingers and web spaces between fingers

• Skin folds around the wrists, elbows, and knees

• Armpits

• Areas around nipples (especially in women)

• Waist

• Penis and scrotum (in men)

• The lower buttocks and upper thighs

• The sides and bottoms of the feet

Scabies in finger’s web spaces. Image credit: DermNetNZ.org via CC BY-NC-ND 3.0 NZ

Scabies around wrist of hand. Image credit: DermNetNZ.org via CC BY-NC-ND 3.0 NZ

Scabies on the abdomen area of a baby. Image credit: DermNetNZ.org via CC BY-NC-ND 3.0 NZ

Treatment of scabies

There are a variety of scabies treatments available, and the choice may depend on several factors, including the age of the patient and the severity of scabies. It’s important to note that patients with scabies and their close contacts (such as family members who stay together or sexual partners), even without any symptom, should receive treatment at the same time.

Permethrin 5% cream/lotion

E.g. A-Scabs

Permethrin is a type of medication used on a skin to get rid of scabies and lice. It is an effective, well-tolerated and safe treatment option for scabies. Here’s how it is used:

• Apply thoroughly on the whole body from the neck down except hair scalp, including all body folds, groin, navel and external genitalia, as well as the skin under the nails after bath. You may apply this at night after shower.

• Leave the lotion on for 8 to 12 hours

• Rinse off with water

• Repeat the application after 1 week

Throughout the application, it’s normal to feel itching, burning sensation and stinging on the skin. Permethrin 5% lotion can be used by children 2 years old and above, as well as adults, including pregnant and breastfeeding women.

Note: The concentration of permethrin used for hair lice is 1%, not the 5% used in scabies. An example of the product is called A-Lice.

Benzyl benzoate 10 - 25% lotion

Benzyl benzoate is also an effective treatment for scabies, and it’s relatively cheaper than permethrin lotion. However, it can be quite troublesome to use.

• Similar to permethrin, benzyl benzoate 25% lotion is applied thoroughly on skin from the neck downwards all over the body, including all bodyfolds, groin, navel and external genitalia, as well as the skin under the nails (except head and face) after bath.

• The lotion is left on the skin for 24 hours (as opposed to 8-12 hours with permethrin). If during this 24-hour period, you wash your hands or shower, benzyl benzoate must be reapplied again.

• Rinse off 24 hours later.

• Repeat application for another 2 days (total 3 applications in 3 days)

If benzyl benzoate 25% lotion is required in children between 2 to 12 years old, the lotion must be diluted to 10% of concentration. This is done by diluting benzyl benzoate 25% with water at a ratio of 1:1 before application. 

Benzyl benzoate 25% lotion should not be used in children below 2 years old, pregnant and breastfeeding women.

Sulphur 6% in petroleum base ointment

Sulphur 6% in petroleum base ointment is the least toxic treatment option for scabies, hence it is suitable for babies,pregnant and breastfeeding women who have scabies. Its usage is similar to benzyl benzoate 25% lotion. 

Others

• Gamma benzene hexachloride/ Lindane 1% (E.g. Scaboma) lotion/cream — It’s a single-application treatment for scabies. However, it should not be used in children below 10 years old, pregnant, breastfeeding women, and people with seizure. It should not be applied after a hot bath as it may enhance absorption of the medication, which can be harmful to health. Note: Lindane 0.1% product is also available for hair lice purposes. 

• Crotamiton 10% ointment — Mainly used in nodular scabies in children. Nodular scabies is a form of scabies that persist even after initial treatment and is thought to be an allergic reaction towards the retained mite parts in the skin.

• Ivermectin — Ivermectin is the only oral medication that is used to treat patients with scabies that are not able to use topical therapy, and is often combined with permethrin benzyl benzoate lotion to treat crusted scabies in patients with AIDS. Fun fact: Ivermectin almost became one of the treatment options for COVID-19 (And no, it was not approved by FDA)

• Oral antibiotics — Antibiotics sometimes are prescribed to patients with scabies NOT to kill the mites but to manage bacterial infection on skin due to constant scratching.

• Antihistamines and corticosteroids — These are used to reduce itchiness. Steroid creams sometimes can also be applied on skin to reduce itchiness.

• Emollients — Emollients help to increase skin moisture, thus reducing skin dryness and redness.

Clean those fomites!

Fomites are your belongings that may still carry the mites, such as your underwear, clothing, towels and bed linen. These items must be cleaned concurrently as you are undergoing treatment for scabies.

1. Wash personal items mentioned above using a hot wash cycle (>50°C) or hot tumble dried to kill the mites.

2. If items cannot be washed, place them in a plastic bag and leave them for 72 hours before airing and reusing. Parasites that do not live on a host will die in 72 hours.

3. Mattresses should be thoroughly vacuumed, ironed or steam cleaned, paying particular attention to the seams.

4. Where possible, amenities such as toilets and chairs should not be shared (until 24 hours after the first treatment).

Use of an insecticide spray for the environment is not necessary.

A word from Doc2Us

If you have any questions related to scabies, you can consult our professional doctors and healthcare professionals on Doc2Us. Doc2Us is a mobile application that allows you to talk to a doctor or any healthcare professionals via text chat at any time and from anywhere. For better communication, you can even send our online doctor images or voice messages related to your medical inquiry.

Download Doc2Us app on Apple App Store, Google Play Store and Huawei App Gallery; or use our web chat at https://web.doc2us.com/

Note: Doc2Us is not for medical emergencies. In the event of urgent medical conditions, please call 999.

Disclaimer: As a service to our users and general public, Doc2Us provides health education contents. Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

References

1. UpToDate - Patient education: Scabies (Beyond the Basics)

2. A Review of Scabies: An Infestation More than Skin Deep

3. BMJ - Treatment of scabies: newer perspectives

Cover image credit: DermNetNZ.org via CC BY-NC-ND 3.0 NZ

Written By

Ms Joyce Toh

Reviewed By

Doc2us Medical Board