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What Are the Symptoms of Crabs?

The main symptoms of crabs are red, micro bite marks and itching around the genitals. You can get them if you’ve had sexual contact with someone who has crabs or through sharing clothing, bed linens, or towels.

What Are Crabs?

Crabs are tiny parasites named for their crab-like appearance. Most measure about 1/16 inch or less in size. Crabs are sometimes so small (especially in the early stages of development) that they are difficult to detect with the naked eye. They infest the genital area and attach to coarse pubic hairs. There, they feed off human blood by biting the skin.

Crabs are often referred to as pubic lice. They are not the same as body lice, which typically infest hair on the head. However, pubic lice may potentially spread to other areas of the body where coarse hair is located, such as the legs, chest, armpits, eyebrows, or beard.

Because these parasites live on the hair, using condoms during sex isn’t very effective at protecting against crabs.

Signs of Crabs

The main symptoms of crabs are itchy bite marks around the genitals. Other signs that you might have crabs include:

  • Itching around the pubic area, often worsening at night. The crabs’ bites trigger an allergic reaction that causes itchiness starting about five days after they first infest your hair.
  • Irritated, inflamed skin around the genital area.
  • Whitish, oval-shaped eggs (known as nits) attached to the base of your pubic hairs.
  • Tiny white or tan lice crawling in your pubic hair or, less commonly, coarse armpit or facial hair. If you look at them under a magnifying glass, they resemble the crabs you’d find on the beach with six legs and two larger arms.
  • Dark spots and bumps around the pubic region where you’ve been bitten, sometimes accompanied by small spots of blood.
  • Tiny blood marks on your underwear from scratching affected areas.
  • Black powder in your underwear.

When crabs aren’t easily visible, it can be difficult to tell what’s causing the itches and bumps around your genitals. If you’re not sure you’re experiencing signs of crabs, your health care provider can examine you for bite marks and identify the lice using a magnifying glass or a microscope.

Treatments for Crabs

There are several pubic lice treatment options available. The most commonly used options are over-the-counter insecticide creams, lotions, or shampoos. These treatments may need to be applied to the affected areas and left on for several hours before washing off, so be sure to follow the directions carefully. The symptoms of crabs typically disappear a week after starting treatment with a medicated lotion or shampoo. If they don’t, you’ll need to do a second round of treatment.

Another option is an oral medication called Ivermectin. These pills are taken in a single dose. If the first treatment isn’t effective after 10 days, another dose may be needed.

When you begin your treatment, wash all clothes, bedding, and towels in hot water that is at least 130 degrees Fahrenheit and dry them on high heat for a minimum of 20 minutes. Any items that cannot be cleaned in a washing machine must be dry-cleaned or sealed in an airtight bag for two weeks.

While crabs have very irritating symptoms, they are relatively easy to treat. If your symptoms don’t go away with over-the-counter products, see a doctor for further treatment.

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