A skin infection brought about by mite infestation, scabies is extremely contagious and brings with it severe itching and discomfort. The parasite that causes scabies is known as Sarcoptes scabiei var. hominis – also known as the ‘human itch mite’. The female mite burrows beneath the skin uppermost layer, but never beneath the stratum corneum. It lays her eggs a couple of hours after an infection. This mite undergoes four developmental stages during its lifetime: egg, larva, molting into a nymph, and finally, an adult mite. It only takes several days for these eggs to hatch and grow into adults, which then repeat the cycle of laying eggs.

Transmission

People who share the same bed are easily infected. The incubation period after contact is about 4-6 weeks. The mite is easily transferred via beddings and shared clothing or towels, or simply through skin-to-skin contact. As this parasite is present worldwide, people of all socioeconomic classes, races, and ages are subject to infection.

Scabies can easily spread among people sharing common facilities. Those living in nursing homes, prisons, or child care institutions are prone to outbreaks. Among adults, scabies can be acquired from sexual partners. Due to being easily transmitted within a family, doctors suggest treatment for the entire family rather than for the person with visible symptoms alone.

Symptoms

      • Visible mite tracks or serpentine burrows which present as small raised lines, either skin-colored or grayish, and measure 1 cm or more.
      • Itching that gets especially worse during nighttime (pruritus). The most commonly affected areas are: on the back, near the area of the shoulder blades; in the armpits; on the and knee bends; at the groin area; on the inside of the wrists; navel; around the waist; on the lower part of the buttocks; on the scrotum and/or the penis; and on the webs of the toes and the fingers. Other areas may also be affected, but it is rare for the mites to settle on the palms and the soles or on skin areas from the neck up. In children, however, infestation can include the neck, the scalp, the face, and palms and soles.
      • Reddish-brown lesions or nodules; scabies rash.

Diagnosis

• A doctor should be consulted once the symptoms typical to scabies are present and or if you believe that you have come in contact with an infected person. No amount of bathing can eliminate scabies. Likewise, OTC preparations are ineffective against the hardy mite and its eggs.
• Diagnosis can be fairly quick and simple if several family members living together under one roof share the same classic symptoms. Microscopic examinations can be made if lesions are detected on the skin.
• The doctor can perform a shave biopsy wherein a very thin skin layer is shaved off and checked under the microscope for confirmation. The mite, its eggs, or its fecal matter can be identified by removing it carefully from the burrow’s end using a needle tip.
• When burrows are found, a test called the burrow ink test (BIT) can be administered. Fountain pen ink is rubbed on the area under consideration, and wiped off with an alcohol pad. The appearance of the tell-tale zigzag pattern would confirm a scabies infection.
• Failure to find the mite, its eggs, or fecal matter does not necessarily mean that a person is not infected. As few as 10 mites can be present on the skin of a person with the infestation.
• The presence of these same burrows can also be confirmed using topical tetracycline, which is applied to the area of the skin under examination. 

Complications

Vigorous scratching of the skin can lead to breaks which make your skin susceptible to a secondary infection like impetigo – a skin infection commonly caused by Staphylococci bacteria or sometimes, Streptococci. This secondary infection can even lead to kidney inflammation known as post-streptococcal glomerulonephritis.

People with vulnerable immune systems – such as those with leukemia or HIV – may develop several complications from a scabies infection. It can be a problematic situation for people who are gravely ill, the elderly, or people with disabilities, and may develop into a more serious form known as crusted (Norwegian) scabies. This involves lesions which are scaly and crusty, beneath which are large numbers of the mite and its eggs, and affecting extensive areas of the skin. This is difficult to treat and is extremely contagious.

Treatment

• Distressing though it is for an infected patient, scabies can be treated as long as the physician’s instructions for treatment are followed to the letter. It is important to note that within a family, the infection can easily be transmitted because the members share a lot of objects which serve as ‘points of contact.’
• The cloth-covered couch at home, for instance, can hold the parasites which can immediately transfer to the next person to sit on it.
• Scabicides are the products used to deal with this infection. They can kill the mites as well as the eggs, and are bought on prescription. It is important to carefully follow the doctor’s instructions or those on the box label because not doing so would prevent a successful treatment or may cause harm to the patient, as these medications are relatively potent.
• For adults, scabicide creams or ointments should be applied on all areas of the skin from the neck down. In children, it should be applied likewise on the scalp and neck because these areas are also affected in kids. Application should come after a thorough cleansing of the body, preferably before bedtime, and left on for the prescribed duration.
• At least 48 hours before treatment, change all the bed sheets and linen and change into clean clothing. Make sure that used clothing is properly washed in hot water. Dry the clothes and linen in a hot dryer or dry-clean them. You can also place the items in a sealed plastic bag for 3 days, as the mites rarely survive 3 days or more when not in contact with human skin.
• It’s possible for the itching to linger several days after the start of treatment, because scabies is an allergic reaction to the mites and their waste. However, if new lesions are observed or if itching continues for more than a month after the initial application of the scabicide, it may be necessary to repeat the treatment. The itching may be soothed with antihistamines.
• Your physician would prescribe separate medication (antibiotics) for the sores that have developed from broken skin due to scratching. You could also bathe in cool water or rub your skin with a washcloth dipped in cold water to relieve the itchiness.

Prevention

Avoid any form of physical contact with persons suspected of having scabies. Furthermore, when a member of your family already has scabies, immediately follow your doctor’s prescribed treatment and wash all possible material at home that may carry the mites. Everyone within the household should be treated as they may already be undergoing the incubation period. Vacuum all areas of the house and dispose of the bag properly.