SCABIES :
Scabies is an intensely pruritic skin infestation caused by the host-specific mite Sarcoptes scabiei hominis. Approximately 300 million cases of scabies are reported worldwide each year.

Signs and symptoms:

Burrows are a pathognomonic sign and represent the intraepidermal tunnel created by the moving female mite. They appear as serpiginous, grayish, threadlike elevations in the superficial epidermis, ranging from 2-10 mm long. High-yield locations for burrows include the following:

*Webbed spaces of the fingers
*Flexor surfaces of the wrists
Elbows
Axillae
Belt line
Feet
Scrotum (men)
Areola (women)
In geriatric patients, scabies demonstrates a propensity for the back, often appearing as excoriations. In infants and small children, burrows are commonly located on the palms and soles.

One- to 3-mm erythematous papules and vesicles are seen in typical distributions in adults. The vesicles are discrete lesions filled with clear fluid, although the fluid may appear cloudy if the vesicle is more than a few days old.

DIFFERENT TYPES OF SCABIES::

*Nodular Scabies :

Nodules occur in 7-10% of patients with scabies, particularly young children. In neonates unable to scratch, pinkish brown nodules ranging in size from 2-20 mm in diameter may develop.

*Crusted scabies :

In crusted scabies, lesions are often hyperkeratotic and crusted and cover large areas. Marked scaling is common, and pruritus may be minimal or absent. Nail dystrophy and scalp lesions may be prominent. The hands and arms are the usual locations for lesions, but all sites are vulnerable.

SECONDARY LESIONS IN SCABIES:

These lesions result from scratching, secondary infection, and/or the host’s immune response against the scabies mites and their products. Characteristic findings include the following:

Excoriations
Widespread eczematous dermatitis
Honey-colored crusting
Postinflammatory hyperpigmentation
Erythroderma
Prurigo nodules
Frank pyoderma