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24.12.2017 Feature Article

Scabies, What You Need To Know

Scabies, What You Need To Know
24.12.2017 LISTEN

SCABIES "ZONGO ITCH, ITCHY"
Scabies is a contagious skin disease caused by very tiny microscopic mites, known as Sarcoptes scabiei. Humans are the only source of infestation

SPREAD:
Transmission is by direct skin-to-skin contact, including sexual contact.

The infested person may not have symptoms, but, still would be able to spread the infestation

Transmission can occur through Fomites: The mite can survive on room surfaces for up to 36 hours, at room temperatures, permitting, the occasional, fomite transmission.

In a community, Spread is related to
Overcrowded conditions
Lack of public awareness
Delayed treatment of primary cases
PERSONS AT RISK FOR SCABIES?
Disease prevalence, is not affected by sex, age, race, socioeconomic status. However,

Poverty and Overcrowding are the 2 most contributing factors. Direct risk factors include

Household members
Sexual partners
Cold weather favor close body and skin contact.
COMMUNITIES AT RISK FOR SCABIES
Inadequate medical facilities
Poor water quantity and sanitary facilities
Overcrowding
Poor personal hygiene
Poverty.
Epidemics occur in marginalized communities, like the Zongo, and among Refugees.

LIFE CYCLE.
Let us do a bit of parasitology.
The scabies mites are small white disc-like arthropods, visible to the naked eye. Female mites (measuring 0.3-0.4mm in length) are responsible for causing the symptoms.

The parasite spends its entire life cycle on or inside the skin.

The cycle, starts when pregnant female mite, burrows under the skin to lay its eggs.

Eggs hatch to larvae, 2-3 days later.
The 3 legged, larvae burrow further up the superficial skin layers, forming short tunnels, known as, pouches.

It takes another 3-4 days, for larvae to molt into 4 legged nymphs, which stay in their pouches to mature,5-7 days later.

Adult male enters female pouches to mate, just once. After mating, female mites become pregnant for the rest of their life.

Pregnant females, leave their pouches to look for new skin areas to burrow and lay fresh eggs.

Skin burrowing and laying of fresh eggs continue for the rest of the female's lifespan of 1-2 months.

Transmission occurs, as impregnated females are transferred, during person-to-person skin-to-skin contact, and via bedding or clothing.

Mites can survive 3 days, outside the body.
SYMPTOMS OF SCABIES.
It can take 10 to 30 days after infestation for symptoms to start. Symptoms develop rapidly, usually within 4 days of infection, in those with previous infestation.

Intractable skin Itch (usually worse at night)
Rash may be papules, vesicles, pustules, and nodular (in adults), associated with

Tracks of small blisters or bumps on the skin
In severe cases, as seen in those with impaired immunity, Crusty or scaly skin lesions, called crusted scabies, Norwegian scabies, may be seen.

Distribution of Rash
In infants, eruptions may be generalized and the small blisters affect the face, Scalp, skin areas behind the ears, the Palms and Soles.

In Adults and older children, it is limited to the interdigital spaces, Wrist flexures, Elbow, Armpit, Penis and Scrotum, Female breasts and genitalia

The rash looks different in those with impaired immunity:

In those with HIV, as mentioned earlier, the skin lesions are diffuse, crusted looking like psoriasis. Lesions are highly contagious in such persons, due to their high parasitic loads.

In Bedridden Persons, rash may be located, primarily, on the back.

Nodular Scabies: This is an exaggerated hypersensitivity response to scabies, and the reactions appear as firm pruritic nodules on the covered body parts, especially the legs..

DIAGNOSIS
A high index of suspicion.
Think of scabies when there is history of itching in the family members, co-workers, group homes.

In adults, rash rarely involves the face and neck, in children, the rash is commonly on the face and neck.

The definitive diagnosis is by Microscopic identification of the mites, eggs and fecal pellets from burrow scraping.

TREATMENT and PREVENTION OF SCABIES
Who needs treatment?
Infected persons and their close contacts, especially

Household members and Sexual contacts, even if they don't have symptoms..

All persons should be treated simultaneously to avoid re-infestations.

Preventing fomite transmission:
Beddings, clothing, and towels used by the infested person, or their household, sexual, and close contacts, anytime during the 3 days before treatment should be decontaminated by washing in hot water, dried at high temperatures, or placed in hot dryer at 60*C, for 10 minutes, or by sealing in plastic bag for 5-7 days. Scabies mites, generally do not survive outside the human skin after 4 days or more.

MEDICATION
Topical Permethrin 5% skin lotion is applied overnight for 10-14 hours.

A second treatment, a week later, is generally recommended, particularly, for crusted scabies.

Oral Ivermectin, a medication used to treat river blindness, (not approved for children under age 5 years), may be used for recurrent scabies, Crusted scabies, Institutional outbreaks and in highly endemic communities

Other topical lotions, that have been used to treat scabies,include:

Lindane
Benzyl benzoate

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