Q.1 Which of the following is characterized by depigmented macules due to autoimmune destruction of melanocytes?
Melasma
Vitiligo
Tinea versicolor
Lentigo
Explanation - Vitiligo is an autoimmune condition where melanocytes are destroyed, leading to well-demarcated depigmented macules.
Correct answer is: Vitiligo
Q.2 A common cause of hyperpigmentation during pregnancy is:
Vitiligo
Melasma
Albinism
Post-inflammatory hypopigmentation
Explanation - Melasma is characterized by symmetrical hyperpigmented patches, often on the face, and is commonly triggered by hormonal changes during pregnancy.
Correct answer is: Melasma
Q.3 Which fungal infection can cause hypopigmented patches on the trunk?
Tinea corporis
Tinea versicolor
Onychomycosis
Candidiasis
Explanation - Tinea versicolor, caused by Malassezia species, produces hypopigmented or hyperpigmented scaly patches, often on the trunk.
Correct answer is: Tinea versicolor
Q.4 Freckles (ephelides) are primarily due to:
Increased melanocyte number
Increased melanin production
Loss of melanocytes
Dermal melanin deposition
Explanation - Freckles are small, pigmented spots due to increased melanin synthesis in epidermal melanocytes without an increase in melanocyte number.
Correct answer is: Increased melanin production
Q.5 Which pigmentation disorder is associated with Addison's disease?
Vitiligo
Post-inflammatory hyperpigmentation
Diffuse hyperpigmentation
Melasma
Explanation - In Addison's disease, excess ACTH stimulates melanocytes, leading to diffuse hyperpigmentation, especially in sun-exposed areas and mucous membranes.
Correct answer is: Diffuse hyperpigmentation
Q.6 Post-inflammatory hyperpigmentation is commonly seen after:
Fungal infections
Inflammatory skin conditions
Albinism
Freckles
Explanation - Damage or inflammation of the skin (like acne or eczema) can lead to increased melanin deposition at the affected site, causing post-inflammatory hyperpigmentation.
Correct answer is: Inflammatory skin conditions
Q.7 Albinism is caused by a defect in:
Melanocyte number
Melanin production enzyme
Dermal melanocytes
Keratinocytes
Explanation - Albinism is a genetic disorder due to defects in enzymes like tyrosinase, required for melanin synthesis, resulting in hypopigmented skin, hair, and eyes.
Correct answer is: Melanin production enzyme
Q.8 Which of the following is a feature of nevus of Ota?
Blue-gray pigmentation along trigeminal nerve
Hypopigmented macules on trunk
Symmetric facial hyperpigmentation
Small brown freckles on cheeks
Explanation - Nevus of Ota is a dermal melanocytosis causing blue-gray patches in the distribution of the ophthalmic and maxillary branches of the trigeminal nerve.
Correct answer is: Blue-gray pigmentation along trigeminal nerve
Q.9 Which vitamin deficiency can lead to hyperpigmentation around the mouth and hands?
Vitamin B12
Vitamin D
Vitamin C
Vitamin A
Explanation - Vitamin B12 deficiency can cause hyperpigmentation, especially on the knuckles, hands, and oral mucosa, along with hematologic and neurologic signs.
Correct answer is: Vitamin B12
Q.10 Which type of melanin is responsible for brown-black skin pigmentation?
Eumelanin
Pheomelanin
Neuromelanin
Allomelanin
Explanation - Eumelanin is the dark brown to black pigment produced by melanocytes, providing most of the skin’s color and protection against UV radiation.
Correct answer is: Eumelanin
Q.11 Which of the following can cause drug-induced hyperpigmentation?
Amiodarone
Hydrocortisone
Metformin
Paracetamol
Explanation - Amiodarone can cause gray-blue pigmentation, especially on sun-exposed areas, due to drug deposition in the dermis and interaction with melanin.
Correct answer is: Amiodarone
Q.12 Which pigmentation disorder shows a 'chalk-white' appearance of the hair and skin at birth?
Albinism
Vitiligo
Piebaldism
Tinea versicolor
Explanation - Piebaldism is a rare genetic disorder characterized by congenital depigmented patches and a white forelock due to absence of melanocytes in those areas.
Correct answer is: Piebaldism
Q.13 Which of the following is most likely to worsen melasma?
Sun exposure
Cold weather
Low humidity
Night-time activities
Explanation - UV radiation stimulates melanocytes, worsening melasma, making sun protection a key component of management.
Correct answer is: Sun exposure
Q.14 Which disorder presents as a 'salt-and-pepper' appearance in the hair and skin?
Vitiligo
Tinea versicolor
Idiopathic guttate hypomelanosis
Scleroderma
Explanation - In systemic sclerosis (scleroderma), the skin may show 'salt-and-pepper' pigmentation due to areas of hypo- and hyperpigmentation.
Correct answer is: Scleroderma
Q.15 Which enzyme is crucial for melanin production in melanocytes?
Tyrosinase
Collagenase
Elastase
Keratinase
Explanation - Tyrosinase catalyzes the conversion of tyrosine to DOPA and then to melanin, a critical step in pigmentation.
Correct answer is: Tyrosinase
Q.16 Which of the following conditions leads to 'ash leaf' hypopigmented macules?
Tuberous sclerosis
Vitiligo
Albinism
Melasma
Explanation - Tuberous sclerosis presents with hypopigmented 'ash leaf' macules due to abnormal melanocyte development.
Correct answer is: Tuberous sclerosis
Q.17 Which pigmentation disorder is characterized by an autosomal dominant inheritance pattern with stable white patches?
Piebaldism
Vitiligo
Melasma
Freckles
Explanation - Piebaldism is inherited in an autosomal dominant pattern and presents with congenital, stable depigmented patches.
Correct answer is: Piebaldism
Q.18 Which of the following causes a 'muddy' brown hyperpigmentation on the face?
Melasma
Vitiligo
Pityriasis alba
Lentigo
Explanation - Melasma presents as symmetric, brownish patches on sun-exposed areas of the face, often with a 'muddy' appearance.
Correct answer is: Melasma
Q.19 Which condition is most likely to present with confetti-like depigmented macules?
Vitiligo
Tinea versicolor
Freckles
Post-inflammatory hypopigmentation
Explanation - Vitiligo can present with small, confetti-like depigmented macules that may coalesce into larger patches.
Correct answer is: Vitiligo
Q.20 Which skin pigmentation disorder is associated with sun-protected areas and systemic involvement?
Addison's disease
Freckles
Melasma
Tinea versicolor
Explanation - Addison's disease causes diffuse hyperpigmentation in sun-protected areas due to elevated ACTH stimulating melanocytes, often with systemic symptoms like fatigue.
Correct answer is: Addison's disease
Q.21 Which pigment is responsible for red-yellow color in skin and hair?
Pheomelanin
Eumelanin
Neuromelanin
Allomelanin
Explanation - Pheomelanin is a reddish-yellow pigment present in hair and lightly pigmented skin, contrasting with dark eumelanin.
Correct answer is: Pheomelanin
Q.22 Which type of lentigo is commonly seen in elderly individuals due to chronic sun exposure?
Solar lentigo
Simple lentigo
Lentigo maligna
Pityriasis versicolor
Explanation - Solar lentigines are benign hyperpigmented macules caused by chronic UV exposure, commonly called 'age spots' or 'liver spots'.
Correct answer is: Solar lentigo
Q.23 Which of the following can lead to drug-induced hypopigmentation?
Hydroquinone
Amiodarone
Minocycline
Doxycycline
Explanation - Hydroquinone, used for skin lightening, can cause localized hypopigmentation if overused or misapplied.
Correct answer is: Hydroquinone
Q.24 Which inherited disorder shows hypopigmentation along with deafness?
Waardenburg syndrome
Albinism
Piebaldism
Tuberous sclerosis
Explanation - Waardenburg syndrome is a genetic disorder with sensorineural deafness, patchy hypopigmentation of hair and skin, and heterochromia of the eyes.
Correct answer is: Waardenburg syndrome
Q.25 Which disorder presents with a grayish-blue patch over the sacral area in infants?
Mongolian spot
Nevus of Ota
Tinea versicolor
Vitiligo
Explanation - Mongolian spots are congenital dermal melanocytosis, commonly seen as gray-blue patches over the sacral or lumbosacral region in infants, especially of Asian or African descent.
Correct answer is: Mongolian spot