Makindo Medical Notes

Related Subjects: |Nikolsky's sign |Koebner phenomenon |Erythema Multiforme |Pyoderma gangrenosum |Erythema Nodosum |Dermatitis Herpetiformis |Lichen Planus |Acanthosis Nigricans |Acne Rosacea |Acne Vulgaris |Alopecia |Vitiligo |Urticaria |Basal Cell Carcinoma |Malignant Melanoma |Squamous Cell Carcinoma |Mycosis Fungoides (Sezary Syndrome) |Xeroderma pigmentosum |Bullous Pemphigoid |Pemphigus Vulgaris |Seborrheic Dermatitis |Pityriasis/Tinea versicolor infections |Pityriasis rosea |Scabies |Dermatomyositis |Toxic Epidermal Necrolysis |Stevens-Johnson Syndrome |Atopic Eczema/Atopic Dermatitis |Psoriasis

Infestation is common, found worldwide, and affects people of all races and social classes. Recurrence of the eruption usually means re-infection has occurred rather than treatment failure.

About

• Scabies is a common and very itchy skin condition
• It is caused by a tiny mite called Sarcoptes Scabiei.
• Can affect all ages but most common in the young and the elderly.

Aetiology

• A delayed type IV hypersensitivity reaction to the mites, their eggs, or excreta
• It occurs approximately 30 days after infestation and is responsible for the intense pruritus that is seen

Spready

• spread by direct skin-to-skin contact with someone who already has scabies
• Sometimes, but rarely, from shared clothing, towels or bedding.
• People with scabies have an average of about a dozen adult mites on their skin
• Norwegian scabies can occur in patients who have a poor immune system or who are elderly and ill due to other conditions.
• There are thousands of scabies mites on the skin in this variant and it is highly contagious.

Risks

• Scabies spreads rapidly under crowded conditions where there is frequent skin-to-skin contact between people, such as in hospitals, institutions, child-care facilities, and nursing homes.
• spread by direct, prolonged, skin-to-skin contact, with a person already infested with scabies. Contact must be prolonged (a quick handshake or hug will usually not spread infestation).
• Infestation is easily spread to sexual partners and household members. Infestation may also occur by sharing clothing, towels, and bedding.

Clinical

• Itching is the main symptom of scabies, usually starting about a month after the mites are picked up. Can affect the whole body apart from the head and neck
• Elderly and infants may develop a rash on their head and neck. The itch often gets worse at night.
• Often common for several people in the same family, and their friends, to become itchy at roughly the same time.
• Rash of scabies is a mixture of scratch marks and tiny red spots; scratched areas may develop crusty sores which can become infected and develop into small pus spots. A widespread rash similar to eczema (dermatitis) is very common.
• The itchy rash can cover much of the body, but the mites are found mainly in the folds of skin between fingers and toes, the palms of the hands, the wrists, ankles and soles of the feet, groins, penis and breasts.
• The scabies mites burrow into the skin in these areas to lay their eggs leaving tiny spots and silver coloured lines on the skin.
• Adult mites are tiny, only about 0.4 mm long, appearing through a magnifying lens or dermatoscope as a tiny dark dot lying at the end of a burrow.

Differentials

• Eczema

Investigations

• Skin scrapping may be sent for examination under a microscope.

Management

• Making sure that you, family members, friends and any sexual contacts are all treated at the same time whether they are itchy or not.
• Several preparations are effective in the treatment of scabies. Of these, permethrin cream and malathion liquid are the ones used most commonly in the U.K.
• Treatment must be applied to all areas of skin below the neck in adults, all areas of skin in children including the scalp, and not just to the itchy parts. The treatment should be left on for at least 12 hours before being washed off.
• When you wash your hands or any part of your body, you should re- apply the treatment to the washed areas again.
• Two treatments, one week apart, are necessary to kill mites that have hatched out from eggs after the first application.
• One normal high temperature wash of bedding and clothes should eradicate mites.
• Items that can't be washed or dry cleaned can be sealed in a plastic bag for at least 1 week, or put in a freezer.
• If caught from a sexual partner, you may need GUM assessment
• Other treatments may include benzyl benzoate and - oral ivermectin for resistant cases.