A boy comes from Bihar with non-anesthetic hypopigmented atrophic patch over face, diagnosis is- (LQ)
Just remember few important points about each disease and you will be able to solve most of the question.
Differential diagnosis of hypopigmented patch / macule
Pityriasis alba (simplex)-
a. Mostly occuring in children (6-'12 years)
b. Hypopigmented macule on face
c. Macule is scaly and has fine scaled, i.e. fine scaled hypopigmented macule/patch.
d. Lesion is recurrent and is more common in the summer.
a. Occurs in young adults.
b. Multiple small hypo pigmented macule on Trunck and shoulders (chest & back)
c. Macule is scaly i.e. fine scaled hypopigmented macules (furfuraceous or rice powder scales)
d. Macules start around hair follicles and then merge with each other to form large areas.
e. Lesions are recurrent
Note- The term pityriasis is used to describe skin condition in which the scale appears similar to bran.
So, any skin disease with pityriasis in its name will be scaly.
Leprosy (Indeterminate. tuberculoid & Borderline tuberculoid)
a. Resident of leprosy endemic area (Bihar, Tamilnadu, Orrisa).
b. Hypopigmented patch, sharply demarcated, may occur at any area.
c. Patch is non-scaly (sometimes slight scales may present)
d. Patch will be Hypoesthetic / anesthetic and atrophic (epidermal atrophy).
e. Regional nerve thickening may present.
Note- Patch of indeterminate leprosy mayor may not be hypoesthetic, whereas tuberculoid leprosy usually has hypoesthetic / anaesthetic patch.
a. Can occur anywhere in body (depending on type of vitiligo ~ areas subjected to repeated friction & trauma are frequently affected, i.e. Dorsum of hands & feet, knee, elbow)
b. Most cases begin between the age of 10-30 years (but can begin at any age)
c. Patch of vitiligo is de pigmented / non-pigmented (in contrast to leprosy where patch is hypopigmented)
d. Patch is sharply marginated.
e. Margins are elevated and hyperpigmented àSalloped hyperpigmented margins
f. Hair in the lesion may loss pigment àleucotrichia
g. Damage to normal skin results in depigmentation àKoebner / isomorphic phenomenon.
h. Trichrome vitiligo à three colors (white, light brown, dark brown) represents different stages of evolution
a. Presents since birth
b. Localized de pigmented / hypopigmented macules
c. Symmetrical involvement of central part of forehead, ventral trunk, upper and lower extremities
d. There is acral sparing.
e. Characteristically areas of hypopigmentation contain hyperpigmented or normally pigmented macules à Islands of hyper pigmentation within the lesions
f. White forelock of scalp hair is characteristic feature which is present since birth, i.e. congenital white forelock. Rest of the scalp hair are normally pigmented.
Neyus achromicus (Nevus depi~mentosus)
a. Presents since birth, but sometimes lesion may missed and patient may present in childhood.
b. Hypopigmented macule on trunk and proximal part of extrimites.
c. Lesions are unilateral.
d. Feathered margins.
e. Hair within the lesions are normal, i.e. no leucotrichia (in contrast to vitiligo)
f. Erythema appearance on massage.
g. Lesions are static (dont grow in size)
a. Presents since birth
b. It is vascular anomaly presents clinically as hypopigmented patch or macule.
c. Most commonly on the upper chest.
d. Lesion is statatic, i.e. persists unchanged throughout the life.
e. Pressure on lesion makes the lesion to disappear and indistinct from surrounding skin.
f. Massage fails to develop erythrna (in contrast to Nevus achromicus)
Hypopigmented macules ("ash leaf spots'') of tuberous sclerosis are associated with:-
a. Shagreen patches (area of thick leathery skin on back & neck)
b. Facial angiofibroma (adenoma sebaceum)
c. Cafe au lait spots
Albinism <oculocutaneous albinism)
a. Albinism should not be considered as a differential diagnosis of hypopigmented macule/patch as there no patch / macule, instead there is diffuse hypopigmentation of skin & hair throughout the body.
b. Associated eye defects à Absence of pigment in iris and retina (eye defects are present in all cases)
Now see the question
a. Information in the question are :-
i. Boy is from Bihar (leprosy endemic areA.
ii. Hypopigmented atrophic patch (Epidermal atrophy is seen in leprosy)
b. So, the boy in question is suffering from leprosy.
c. Now the question arises whether it is indeterminate (option C.) or borderline (option D.).
d. There is one more important information in question, i.e. Patch is non-anaesthetic àPatch of
e. Indeterminate leprosy mayor may not be anaesthetic whereas patch of tuberculoid leprosy and borderline tuberculoid leprosy is usually anaesthetic / hypoesthetic.
f. So, the diagnosis is inderminate leprosy.
About other options
P. versicolor and P. alba will have scaly patch without atrophy.