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Final exam 2020
1. A patch test involves applying a chemical to the skin and then watching for
dermatitis to develop 48 –96 h later. The test result ++ Strong reaction means?
a. Minimal erythema.
b. Glazed appearance and increased skin markings
c. Erythema and may be papules.
d. Palpable erythema and/or vesicle
e. erythema and petechia
Answer
—D—
The test detects type IV delayed hypersensitivity reactions. Interpretation of
Results:
±Doubtful reaction (minimal erythema).
+Weak positive reaction (erythema and may be papules).
++Strong reaction (palpable erythema and/or vesicles).
Final exam 2020 1
, +++Extreme reaction (vesicles and/or bullae).
IR Irritant reaction
Lec: Diagnosis of Skin disorders
2. Clinically lichen planus will shows ?
a. the nails are unaffected
b. the Köbner phenomenon is rare
c. excoriations are common
d. scalp scarring alopecia
e. White symptomatic oral lacy lines
Answer
—D—
White asymptomatic lacy lines, dots, and occasionally small white plaques,
are also found in the mouth, particularly inside the cheeks, in about 50%of
patients, and oral lesions may be the sole manifestation of the disease The
nails are usually normal, but in about10% of patients show changes ranging
from fine longitudinal grooves to destruction of the entire nail fold and bed
As in psoriasis, the Köbner phenomenon may occur. Scalp lesions can
cause a patchy scarring alopecia. Curiously, although the skin plaques
are usually itchy, patients rub rather than scratch, so that excoriations are
uncommon
Lec: Papulosquamous disorders
3. A patient gets recurrent urticaria while doing exercising and on exposure to sunlight.
Which of the following is the most likely cause?
a. Chronic idiopathic urticaria
b. Solar urticaria
c. Universal dermographism
Final exam 2020 2
, d. Cholinergic urticaria
e. aquagenic urticaria
Answer
—D—
Cholinergic urticaria : Anxiety, heat, sexual excitement or strenuous
exercise. The vessels over-react to acetylcholine liberated from sympathetic
nerves in the skin
Aquagenic urticaria : precipitated by contact with water, irrespective of its
temperature.
Solar urticaria : within minutes of sun exposure.
Dermographism: This is the most common type of physical urticaria, the
skin mast cells releasing extra histamine after rubbing or scratching
Chronic idiopathic urticaria (CIU) is defined as the occurrence of close-to-
daily wheals and pruritus for a duration of at least 6 weeks, without an
obvious cause
Lec: Uricaria
4. hair dye Dermatitis caused by
a. oak.
b. nickel
c. Quratinum 15
d. formaldehyde .
e. paraphenylenediamine.
Answer
—E—
Examples of Allergic Contact Dermatitis :
Ear lobe dermatitis ;nickel ( most common allergens)allergy due to earrings.
Cement dermatitis; potassium dichromate allergy.
Shoe dermatitis ; leather or rubber allergy .
Eyelid dermatitis ;nail varnish, local medication, cosmetics &air born demerititis
Final exam 2020 3
, Hair dye dermatitis ; paraphenelydiamine PPD.
Phytophotodermatitis; plant dermatitis; e.g. poison of ivy, oak &sumac
Lec: exogenous eczema
5. Ecthyma is skin infection characterized by ulceration that is covered by adherent
crust. Ecthyma is caused by
a. Sarcoptes scabiei.
b. Staphylococcus aureus.
c. Leishmania aethiopica.
d. Mycobacterium leprae.
e. Treponema pallidum.
Answer
—B—
Ecthyma is a deep bacterial infection that involves the dermis. It is caused by
streptococci, staphylococci or both.
Lec: Bacterial infections
6. In tinea capitis, the trichophyton that produce pale green fluorescence on Wood’s
light examination is
a. Trichophyton schoenleinii.
b. Trichophyton rubrum.
c. Trichophyton mentagrophytes.
d. Trichophyton verrucosum.
e. Trichophyton interdigitale
Answer
—A—
Wood’s light examination: it is a device gives light rays with wave length above
365 nm. Hairs fluoresce with a blue-green fluorescence if infected with
microsporum species. Hairs fluoresce pale green fluorescence if infected with
Final exam 2020 4
Final exam 2020
1. A patch test involves applying a chemical to the skin and then watching for
dermatitis to develop 48 –96 h later. The test result ++ Strong reaction means?
a. Minimal erythema.
b. Glazed appearance and increased skin markings
c. Erythema and may be papules.
d. Palpable erythema and/or vesicle
e. erythema and petechia
Answer
—D—
The test detects type IV delayed hypersensitivity reactions. Interpretation of
Results:
±Doubtful reaction (minimal erythema).
+Weak positive reaction (erythema and may be papules).
++Strong reaction (palpable erythema and/or vesicles).
Final exam 2020 1
, +++Extreme reaction (vesicles and/or bullae).
IR Irritant reaction
Lec: Diagnosis of Skin disorders
2. Clinically lichen planus will shows ?
a. the nails are unaffected
b. the Köbner phenomenon is rare
c. excoriations are common
d. scalp scarring alopecia
e. White symptomatic oral lacy lines
Answer
—D—
White asymptomatic lacy lines, dots, and occasionally small white plaques,
are also found in the mouth, particularly inside the cheeks, in about 50%of
patients, and oral lesions may be the sole manifestation of the disease The
nails are usually normal, but in about10% of patients show changes ranging
from fine longitudinal grooves to destruction of the entire nail fold and bed
As in psoriasis, the Köbner phenomenon may occur. Scalp lesions can
cause a patchy scarring alopecia. Curiously, although the skin plaques
are usually itchy, patients rub rather than scratch, so that excoriations are
uncommon
Lec: Papulosquamous disorders
3. A patient gets recurrent urticaria while doing exercising and on exposure to sunlight.
Which of the following is the most likely cause?
a. Chronic idiopathic urticaria
b. Solar urticaria
c. Universal dermographism
Final exam 2020 2
, d. Cholinergic urticaria
e. aquagenic urticaria
Answer
—D—
Cholinergic urticaria : Anxiety, heat, sexual excitement or strenuous
exercise. The vessels over-react to acetylcholine liberated from sympathetic
nerves in the skin
Aquagenic urticaria : precipitated by contact with water, irrespective of its
temperature.
Solar urticaria : within minutes of sun exposure.
Dermographism: This is the most common type of physical urticaria, the
skin mast cells releasing extra histamine after rubbing or scratching
Chronic idiopathic urticaria (CIU) is defined as the occurrence of close-to-
daily wheals and pruritus for a duration of at least 6 weeks, without an
obvious cause
Lec: Uricaria
4. hair dye Dermatitis caused by
a. oak.
b. nickel
c. Quratinum 15
d. formaldehyde .
e. paraphenylenediamine.
Answer
—E—
Examples of Allergic Contact Dermatitis :
Ear lobe dermatitis ;nickel ( most common allergens)allergy due to earrings.
Cement dermatitis; potassium dichromate allergy.
Shoe dermatitis ; leather or rubber allergy .
Eyelid dermatitis ;nail varnish, local medication, cosmetics &air born demerititis
Final exam 2020 3
, Hair dye dermatitis ; paraphenelydiamine PPD.
Phytophotodermatitis; plant dermatitis; e.g. poison of ivy, oak &sumac
Lec: exogenous eczema
5. Ecthyma is skin infection characterized by ulceration that is covered by adherent
crust. Ecthyma is caused by
a. Sarcoptes scabiei.
b. Staphylococcus aureus.
c. Leishmania aethiopica.
d. Mycobacterium leprae.
e. Treponema pallidum.
Answer
—B—
Ecthyma is a deep bacterial infection that involves the dermis. It is caused by
streptococci, staphylococci or both.
Lec: Bacterial infections
6. In tinea capitis, the trichophyton that produce pale green fluorescence on Wood’s
light examination is
a. Trichophyton schoenleinii.
b. Trichophyton rubrum.
c. Trichophyton mentagrophytes.
d. Trichophyton verrucosum.
e. Trichophyton interdigitale
Answer
—A—
Wood’s light examination: it is a device gives light rays with wave length above
365 nm. Hairs fluoresce with a blue-green fluorescence if infected with
microsporum species. Hairs fluoresce pale green fluorescence if infected with
Final exam 2020 4
