Parasitic infestations can cause significant discomfort, often presenting with symptoms like intense itching. While scabies and “crabs” both fall into this category, they are distinct conditions caused by different organisms that target different areas of the body. Understanding their unique characteristics is important for accurate identification and effective management.
What is Scabies?
Scabies is a skin infestation caused by a microscopic mite named Sarcoptes scabiei var. hominis. The mite burrows into the outermost layer of human skin, where the female lays its eggs. The presence of the mites, their eggs, and their waste products triggers an allergic reaction, causing symptoms.
The primary symptom of scabies is intense itching, which often worsens at night. A rash commonly appears as small, red bumps or pimple-like lesions, and sometimes visible, thin, wavy burrow tracks can be seen on the skin. Common areas affected include the skin between the fingers, wrists, elbows, armpits, waistline, genitals, and buttocks. Scabies typically spreads through prolonged direct skin-to-skin contact with an infested person, such as during intimate contact or living in close quarters.
What are Crabs?
“Crabs,” scientifically known as pubic lice, are caused by a parasitic insect called Pthirus pubis. These tiny insects are named for their crab-like appearance under magnification. Unlike scabies mites, pubic lice do not burrow into the skin but instead cling to coarse body hairs and feed on human blood.
Pubic lice primarily infest the pubic hair around the genitals, but they can also be found in other areas with coarse hair, such as the armpits, chest, thighs, beard, mustache, and, in some cases, eyelashes. Symptoms include intense itching in the affected areas, and small red or bluish spots may appear on the skin where the lice have bitten. Visible nits (eggs) attached to the hair shafts or adult lice can also be observed. Pubic lice are most commonly transmitted through sexual contact, but they can also spread through close personal contact or by sharing infested bedding, towels, or clothing.
How to Tell the Difference
Distinguishing between scabies and crabs involves recognizing key differences in the parasite, affected body areas, appearance of the infestation, and modes of transmission. The causative agent for scabies is a microscopic mite that burrows into the skin, while crabs are caused by a visible louse that clings to hair.
Scabies typically manifests as a rash and burrows on thinner skin, often appearing between the fingers, on the wrists, elbows, or waistline. In contrast, crabs are found primarily in coarse body hair, most commonly the pubic region, but also armpits or facial hair. Scabies presents with pimple-like bumps, a rash, and sometimes visible burrow lines, whereas crabs involve visible lice or their tiny white eggs (nits) attached to hair, along with potential blue spots from bites.
Transmission methods further differentiate the two conditions. Scabies primarily spreads through prolonged skin-to-skin contact. Pubic lice, however, are predominantly transmitted through sexual contact, though close non-sexual contact or shared items can also lead to spread.
Getting Rid of and Preventing Infestations
Treating both scabies and crabs requires specific medications to eliminate the parasites. For scabies, topical creams or lotions containing ingredients like permethrin are commonly prescribed and applied to the entire body from the neck down. Oral medication like ivermectin may be used for widespread or severe infestations. For pubic lice, medicated shampoos or lotions, often containing permethrin or pyrethrins, are applied to the affected hairy areas.
It is important that all close contacts of an infested individual also receive treatment to prevent reinfestation and further spread. After treatment, itching may persist for a few weeks as the skin recovers from the allergic reaction. Consulting a healthcare professional for an accurate diagnosis and treatment plan is always recommended.
Prevention strategies involve limiting exposure to the parasites. To prevent scabies, avoiding prolonged skin-to-skin contact with infested individuals is important. Washing all clothing, bedding, and towels used by an infested person in hot water and drying them on a high heat cycle also helps eliminate mites. For crabs, practicing safe sexual contact and refraining from sharing personal items such as towels, clothing, or bedding can reduce the risk of transmission.