Scabies - Clinicals, Diagnosis, and Management

Dermatology

Clinicals - History

Fact Explanation
Pruritus : Characteristically at night or after a hot bath Immune response to mites and its excreta Pruritus : Characteristically at night or after a hot bath
Immune response to mites and its excreta
Rash : Papules/ Nodules/ Vesicles/ Eczematous Immune response to mites and its excreta Rash : Papules/ Nodules/ Vesicles/ Eczematous
Immune response to mites and its excreta
Sites of lesions : Interdigital spaces and the flexor surfaces of the wrist, axillae, waist, feet, ankles. In females the skin surrounding the nipple, In males the scrotum and penis is involved Commonest sites for scabies mite for burrowing Sites of lesions : Interdigital spaces and the flexor surfaces of the wrist, axillae, waist, feet, ankles. In females the skin surrounding the nipple, In males the scrotum and penis is involved
Commonest sites for scabies mite for burrowing
Contact history of Scabies infection : Family members/ Institutional setting The commonest route of transmission is direct skin-to-skin contact Contact history of Scabies infection : Family members/ Institutional setting
The commonest route of transmission is direct skin-to-skin contact
Fever Following secondary bacterial infection Fever
Following secondary bacterial infection

Clinicals - Examination

Fact Explanation
Rash: Papules/ Nodules/ vesicles/ Pustules often accompanied by eczematous lesions. Symmetrically distributed. Sites : on the volar wrists, between the fingers, on the elbows, and on the penis, In skin folds under the breasts and around the navel, axillae, belt line, buttocks, upper thighs, and scrotum sensitization reaction against the excreta of the mite present in the burrows Rash: Papules/ Nodules/ vesicles/ Pustules often accompanied by eczematous lesions. Symmetrically distributed. Sites : on the volar wrists, between the fingers, on the elbows, and on the penis, In skin folds under the breasts and around the navel, axillae, belt line, buttocks, upper thighs, and scrotum
sensitization reaction against the excreta of the mite present in the burrows
In Infants: In addition to the above sites the face, scalp, neck, palms, and soles are also involved sensitization reaction against the excreta of the mite present in the burrows In Infants: In addition to the above sites the face, scalp, neck, palms, and soles are also involved
sensitization reaction against the excreta of the mite present in the burrows
Burrows - They are seen by appear as dark wavy lines and measure up to 5 mm. Commonest locations are on the volar wrists, between the fingers, on the elbows, and on the penis The scabies mite makes the burrow by digesting and consuming the horny layer of the epidermis Burrows - They are seen by appear as dark wavy lines and measure up to 5 mm. Commonest locations are on the volar wrists, between the fingers, on the elbows, and on the penis
The scabies mite makes the burrow by digesting and consuming the horny layer of the epidermis
Secondary infection of lesions Due secondary bacterial infections Secondary infection of lesions
Due secondary bacterial infections
Crusted Scabies - Presents as a psoriasiform dermatitis with a peripheral distribution. Erythematous scaly eruption involving the face, neck, scalp, and trunk Due to hyperinfestation with thousands of mites Crusted Scabies - Presents as a psoriasiform dermatitis with a peripheral distribution. Erythematous scaly eruption involving the face, neck, scalp, and trunk
Due to hyperinfestation with thousands of mites

Investigations - Diagnosis

Fact Explanation
Demonstration of Mite/ Eggs/ Fecal pellets from Burrows Sarcoptes scabei mite/ eggs/ Fecal pellets Demonstration of Mite/ Eggs/ Fecal pellets from Burrows
Sarcoptes scabei mite/ eggs/ Fecal pellets
Biopsies, scrapings of papulovesicular lesions, and microscopic inspection of clear adhesive tape lifted from lesions Demonstration of Mite/ Eggs/ Fecal pellets Biopsies, scrapings of papulovesicular lesions, and microscopic inspection of clear adhesive tape lifted from lesions
Demonstration of Mite/ Eggs/ Fecal pellets

Investigations - Management

Fact Explanation
Repeat of Biopsies, scrapings of papulovesicular lesions, and microscopic inspection of clear adhesive tape lifted from lesions one month after treatment Evidence of cure requires follow up for almost one month. As this allows time for lesions to heal and for any eggs and mites to
reach maturity in case of treatment failure
Repeat of Biopsies, scrapings of papulovesicular lesions, and microscopic inspection of clear adhesive tape lifted from lesions one month after treatment
Evidence of cure requires follow up for almost one month. As this allows time for lesions to heal and for any eggs and mites to
reach maturity in case of treatment failure
Renal function tests Secondary infection of skin lesions by group A β-hemolytic streptococci may increase the risk of the child developing Glomerulonephritis Renal function tests
Secondary infection of skin lesions by group A β-hemolytic streptococci may increase the risk of the child developing Glomerulonephritis
Skin biopsy for Histology Demonstration of nonspecific, delayed hypersensitivity reaction Skin biopsy for Histology
Demonstration of nonspecific, delayed hypersensitivity reaction

Management - Supportive

Fact Explanation
All bedding, towels, and clothing should be washed in warm water. To eradicate Scabies mite All bedding, towels, and clothing should be washed in warm water.
To eradicate Scabies mite
Patients should be instructed to avoid contact with their sex partner until they have been treated and both individuals have been seen in follow-up The commonest route of transmission is direct skin-to-skin contact Patients should be instructed to avoid contact with their sex partner until they have been treated and both individuals have been seen in follow-up
The commonest route of transmission is direct skin-to-skin contact
Anithistamines - To reduce pruritus antihistamines reduces histamine release associated with the Immune response to scabies mites and its excreta Anithistamines - To reduce pruritus
antihistamines reduces histamine release associated with the Immune response to scabies mites and its excreta
Antibiotics oral/ Topical - According to Antibiotic sensitivity test Due secondary bacterial infections Antibiotics oral/ Topical - According to Antibiotic sensitivity test
Due secondary bacterial infections

Management - Specific

Fact Explanation
Permethrin 5% - Topical. Applied overnight once a week for two weeks to the entire body, including the head in infants. For a contact period of eight hours. Effective scabicide. Low side effects, can be used safely in children. Treat all household contacts. , Permethrin 5% - Topical. Applied overnight once a week for two weeks to the entire body, including the head in infants. For a contact period of eight hours.
Effective scabicide. Low side effects, can be used safely in children. Treat all household contacts. ,
Benzyl benzoate - 10% / 25%. : Should be applied below the neck three times within 24 hours without an intervening bath Effective scabicide. Neurotoxic to mites. Contraindicated in pregnancy, lactation, infants, and children less than 2 years of age Benzyl benzoate - 10% / 25%. : Should be applied below the neck three times within 24 hours without an intervening bath
Effective scabicide. Neurotoxic to mites. Contraindicated in pregnancy, lactation, infants, and children less than 2 years of age
Ivermectin - Oral anti scabies drug Neurotoxic to scabies mite. Relatively safe. however contraindicated in patients' with CNS disease, pregnancy, lactation, and in children less than 5 years of age. Ivermectin - Oral anti scabies drug
Neurotoxic to scabies mite. Relatively safe. however contraindicated in patients' with CNS disease, pregnancy, lactation, and in children less than 5 years of age.
Lindane lotion - 1% {1} No longer recommended due to CNS toxicity Lindane lotion - 1% {1}
No longer recommended due to CNS toxicity
Malathion Kills the mite due to organophosphate insecticide that irreversibly blocks the enzyme acetylcholinesterase. It is not recommended for humans now due to side effect profile Malathion
Kills the mite due to organophosphate insecticide that irreversibly blocks the enzyme acetylcholinesterase. It is not recommended for humans now due to side effect profile

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