Q.1 What is the causative organism of scabies?
Sarcoptes scabiei
Demodex folliculorum
Pediculus humanus
Culex mosquito
Explanation - Scabies is caused by the mite Sarcoptes scabiei, which burrows into the skin.
Correct answer is: Sarcoptes scabiei
Q.2 Which symptom is most characteristic of scabies?
Painless blisters
Nocturnal itching
Hair loss
Photosensitivity
Explanation - Itching at night is a hallmark symptom due to increased mite activity in warmth.
Correct answer is: Nocturnal itching
Q.3 Which skin lesion is pathognomonic for scabies?
Burrows
Macules
Vesicles
Papules
Explanation - Burrows, thin linear tracks in the skin, are diagnostic of scabies.
Correct answer is: Burrows
Q.4 What is the first-line treatment for scabies?
Permethrin cream
Oral acyclovir
Topical corticosteroids
Oral doxycycline
Explanation - Permethrin 5% cream is the first-line treatment for scabies infestation.
Correct answer is: Permethrin cream
Q.5 Which part of the body is most often affected by scabies in adults?
Face
Palms and soles
Web spaces of fingers
Scalp
Explanation - Scabies mites commonly burrow in interdigital web spaces of fingers.
Correct answer is: Web spaces of fingers
Q.6 How is scabies transmitted?
Airborne droplets
Skin-to-skin contact
Fecal contamination
Mosquito bite
Explanation - Scabies is transmitted by prolonged direct skin-to-skin contact.
Correct answer is: Skin-to-skin contact
Q.7 Which of the following populations is most prone to crusted scabies?
Healthy adults
Infants
Immunocompromised patients
Teenagers
Explanation - Crusted scabies occurs in immunocompromised or debilitated individuals.
Correct answer is: Immunocompromised patients
Q.8 What is a common complication of scabies due to scratching?
Eczema
Impetigo
Psoriasis
Vitiligo
Explanation - Secondary bacterial infection such as impetigo often complicates scabies.
Correct answer is: Impetigo
Q.9 Which diagnostic tool is used to confirm scabies?
Skin scraping
Wood’s lamp test
Patch testing
Tzanck smear
Explanation - Microscopic examination of skin scrapings reveals mites, eggs, or feces.
Correct answer is: Skin scraping
Q.10 What is the incubation period of scabies in a previously unexposed person?
1–2 days
4–6 weeks
7–10 days
12 hours
Explanation - Scabies symptoms may take 4–6 weeks to appear in new infestations.
Correct answer is: 4–6 weeks
Q.11 Which of the following is NOT a typical site of scabies infestation?
Interdigital spaces
Genital region
Elbow folds
Scalp in adults
Explanation - The scalp is usually spared in adults, but infants may have scalp involvement.
Correct answer is: Scalp in adults
Q.12 Which oral medication can be used for refractory scabies?
Ivermectin
Fluconazole
Azithromycin
Isotretinoin
Explanation - Oral ivermectin is used in refractory cases or for crusted scabies.
Correct answer is: Ivermectin
Q.13 Which age group is most likely to have scalp involvement in scabies?
Infants
Teenagers
Adults
Elderly
Explanation - In infants, scabies commonly involves the scalp, unlike in adults.
Correct answer is: Infants
Q.14 Which mite causes human scabies?
Sarcoptes scabiei var. hominis
Ixodes scapularis
Dermacentor variabilis
Cheyletiella yasguri
Explanation - The human variant of Sarcoptes scabiei causes scabies in humans.
Correct answer is: Sarcoptes scabiei var. hominis
Q.15 In which condition do patients present with thick crusts containing thousands of mites?
Crusted scabies
Atopic dermatitis
Seborrheic dermatitis
Ringworm
Explanation - Crusted scabies is characterized by heavy mite infestation and thick crusts.
Correct answer is: Crusted scabies
Q.16 How long can scabies mites survive off the human body?
Less than 24 hours
2–3 days
1 week
Several months
Explanation - Mites can survive for up to 2–3 days outside the host, leading to indirect transmission.
Correct answer is: 2–3 days
Q.17 Which household measure is recommended in scabies management?
Avoid bathing
Wash bedding in hot water
Cover skin with bandages
Apply cold compresses only
Explanation - Washing bedding and clothes in hot water helps eliminate mites.
Correct answer is: Wash bedding in hot water
Q.18 Which sign refers to visible mite burrows in scabies?
Delta wing sign
Burrow track sign
Boil sign
Bull’s-eye sign
Explanation - The delta wing sign on dermoscopy indicates the mite at the end of a burrow.
Correct answer is: Delta wing sign
Q.19 Which parasite causes pediculosis?
Lice
Mites
Fleas
Ticks
Explanation - Pediculosis is infestation by lice, distinct from scabies caused by mites.
Correct answer is: Lice
Q.20 Which insect is responsible for tungiasis?
Tunga penetrans
Cimex lectularius
Anopheles mosquito
Glossina morsitans
Explanation - Tunga penetrans, the sand flea, burrows into skin causing tungiasis.
Correct answer is: Tunga penetrans
Q.21 What is the main difference between head lice and scabies infestation?
Mode of transmission
Nocturnal itching
Burrows in skin
Associated with poor hygiene
Explanation - Scabies causes burrows, while head lice infest hair shafts without burrowing.
Correct answer is: Burrows in skin
Q.22 Which of the following is NOT an ectoparasite?
Mite
Flea
Louse
Plasmodium
Explanation - Plasmodium is a protozoan parasite, not an ectoparasite.
Correct answer is: Plasmodium
Q.23 Which ectoparasite causes nocturnal bites, often found in bedding?
Bed bugs
Fleas
Ticks
Mites
Explanation - Bed bugs (Cimex lectularius) feed at night and hide in bedding.
Correct answer is: Bed bugs
Q.24 Which condition is transmitted by Ixodes ticks?
Lyme disease
Scabies
Pediculosis
Onchocerciasis
Explanation - Ixodes ticks transmit Borrelia burgdorferi causing Lyme disease.
Correct answer is: Lyme disease
Q.25 In scabies, which immune response leads to itching?
Immediate hypersensitivity
Delayed hypersensitivity
Autoimmune response
IgE-mediated allergy
Explanation - Itching in scabies is due to delayed hypersensitivity to mite antigens.
Correct answer is: Delayed hypersensitivity