Particularly in early stages of infestation with the causative parasitic mites, the symptoms of scabies have an unspecific character and can be easily confused with the manifestations of skin disorders such as eczema, seborrhea, chicken pox (especially in children) or other viral rashes. In order to accurately diagnose persons with scabies, doctors often examine the regions of affected skin under the microscope, looking for clear signs of the presence of scabies mites. Doctors can accurately diagnose scabies only after finding traces of the mites within the superficial layers of the skin (usually eggs and feces inside tiny burrows).

Scabies mites usually infest the skin regions between the fingers and toes, the regions of the wrists, elbows, feet, ankles, knees, armpits, nipples, lower abdomen and genitals. The parasitic mites responsible for causing scabies rarely infest the neck skin or the face (such rare cases of scabies occur in small children and infants).

The incubation period of scabies can vary anywhere from several days to four weeks. Most symptoms of scabies occur within this interval of time and the first clinical sign of infestation with scabies mites is skin rash. Scabies rash is associated with severe itching, sensations of burning or tenderness and occurs under the form of red patches on the surface of the skin. Scabies rash and pronounced itching sensation are caused by allergic reactions to the mites’ eggs and feces, as well as saliva (scabies mites feed off the skin of their hosts). Persons with scabies should avoid scratching the affected regions of the skin in order to minimize the risk of bacterial infections. Later symptoms of scabies include scaling of the skin, the formation of hardened crust, the occurrence of tiny blisters and bumps. The symptoms of scabies tend to intensify after a hot bath or at night.

Unlike common scabies, crusted scabies (also referred to as Norwegian scabies) can produce severe symptoms in a relatively short period of time. Norwegian scabies is highly contagious and predominantly occurs in elderly people and in persons with immune system deficiency (AIDS patients). Crusted scabies includes the symptoms of common scabies and is also manifested by intense scaling of the affected skin and the formation of thick, hardened crust. Unlike common scabies, crusted scabies may involve little or no itching. Crusted scabies is difficult to treat, as the medications used to eradicate the infestation with mites are not properly absorbed inside the skin, having a reduced effect. The treatment of crusted scabies requires a course of stronger scabies medications.