What is the treatment for scabies in adults?

From the Guidelines

The first-line treatment for adult scabies is permethrin 5% cream, applied from neck to toes and left on for 8-14 hours before washing off, as recommended by the most recent guidelines 1. This treatment should be repeated after 7 days to kill newly hatched mites. Alternatively, oral ivermectin can be used at a dose of 200 mcg/kg, with a second dose given 1-2 weeks later. For severe or crusted scabies, a combination of both treatments may be necessary. All household members and close contacts should be treated simultaneously, even if asymptomatic, to prevent reinfestation. Clothing, bedding, and towels used in the previous 3 days should be washed in hot water and dried on high heat, as recommended by the Centers for Disease Control and Prevention 1. Itching may persist for 2-4 weeks after successful treatment due to an allergic reaction to dead mites, and symptomatic relief can be provided with antihistamines or topical steroids. Permethrin works by paralyzing the nervous system of mites, while ivermectin disrupts their neurotransmission, both leading to parasite death and elimination of the infestation. Retreatment 2 weeks after the initial treatment regimen can be considered for those persons who are still symptomatic or when live mites are observed, and use of an alternative regimen is recommended for those persons who do not respond initially to the recommended treatment 1.

Some key considerations for management of scabies include:

• Decontamination of bedding and clothing by machine-washing, machine-drying using the hot cycle, or dry cleaning, or removing from body contact for at least 72 hours 1
• Keeping fingernails closely trimmed to reduce injury from excessive scratching 1
• Avoiding fumigation of living areas, as it is unnecessary 1
• Providing symptomatic relief with antihistamines or topical steroids for itching that persists after successful treatment 1

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Adults and children Thoroughly massage Permethrin Cream, 5% into the skin from the head to the soles of the feet. Scabies rarely infests the scalp of adults, although the hairline, neck, temple, and forehead may be infested in infants and geriatric patients. Usually 30 grams is sufficient for an average adult. The cream should be removed by washing (shower or bath) after 8 to 14 hours. ONE APPLICATION IS GENERALLY CURATIVE. Demonstrable living mites after 14 days indicate that retreatment is necessary.

The treatment for scabies in adults is to apply Permethrin Cream, 5% from the head to the soles of the feet, with one application generally being curative 2.

• Massage the cream into the skin
• Remove the cream by washing after 8 to 14 hours
• Retreatment may be necessary if living mites are still present after 14 days

Alternatively, Crotamiton lotion can be used, with a second application advisable 24 hours later 3.

• Massage the lotion into the skin from the chin to the toes
• Pay particular attention to all folds and creases
• Change clothing and bed linen the next day
• Take a cleansing bath 48 hours after the last application

From the Research

Treatment Options for Scabies in Adults

• The primary treatment for scabies in adults is topical permethrin 5% cream 4, 5, 6, 7.
• Permethrin 5% cream should be applied to all external surfaces of the body, including the scalp and head, in some cases 4.
• The cream should be left on the skin for 24 hours and repeated 7-10 days later 5.
• Alternative treatment options include topical ivermectin, which has been shown to be as effective as permethrin 2.5% cream in some studies 8.
• It is essential to wash clothing and bedding in hot water and dry them in a hot dryer to prevent re-infestation 7.

Application and Dosage

• Topical permethrin 5% cream should be applied once daily, either as a single application or for two consecutive days 5.
• The cream should be stored in the refrigerator and applied cold to the entire skin surface 5.
• The treatment should be repeated 7-10 days later, and follow-up should be done 2 months after the end of treatment 5.

Efficacy and Safety

• The cure rate for permethrin 5% cream has been reported to be as high as 95.1% 6.
• Permethrin 5% cream is generally well-tolerated, with mild side effects such as irritant contact dermatitis reported in some cases 5, 6.
• Topical ivermectin has also been shown to be effective, with a cure rate of 84.2% at the 4-week follow-up 8.