More than 300 million cases of scabies occur worldwide every year, according to the American Academy of Dermatology. Scabies is a parasitic skin infection caused by tiny mites that burrow under the skin. Scabies infections often show no signs for the first two to six weeks. Scabies is highly contagious and transferred through skin to skin contact. Symptoms of scabies can initially mimic many other skin disorders such as contact dermatitis. However, there are some telltale signs that distinguish scabies from other common rashes.
Itching
Severe itching is often the first sign of a scabies infestation. While many skin disorders present with itching, scabies sufferers report itching so intense that they often cause damage to the skin attempting to alleviate the itch. People with scabies may notice that the itching seems much worse at night.
Rash
A rash will often appear on the infected areas of the skin. According to the Centers for Disease Control and Prevention, the rash is caused by an allergic reaction to the proteins and feces of the mite under the skin. The mites will most often burrow under the skin folds or in moist tissues. This most commonly includes between the fingers, around the waist, in the armpits, at the groin, around the shoulder blades and along the inside of wrists. A scabies rash may show signs of small white blisters or vesicles with tiny black dots. The mites enter where the tiny white blisters appear and the black dot is the mite itself. Tracks may also be present where the mite travels under the skin.
Sores
Sores often develop on the skin where the mites break through to burrow underneath. A patient's vigorous scratching may also cause broken skin, which can lead to secondary bacterial infections such as impetigo caused by the staphylococcus bacteria or even by streptococci bacteria. The Mayo Clinic says that in a severe form of scabies, known as crusted scabies, the sores may be crusty and scaly and cover large areas of the body.
