DERMATOPHYTES
Q. 1
Most common organism causing tinea capitis in India is:
| A | Microsporum | |
| B | Trichophyton tonsurans | |
| C | Epidermophyton | |
| D | Trichophyton violaceum |
Q. 1
Most common organism causing tinea capitis in India is:
| A | Microsporum | |
| B | Trichophyton tonsurans | |
| C | Epidermophyton | |
| D | Trichophyton violaceum |
Explanation:
The most common organisms causing Tinea capitis in the United States are Trichophyton tonsurans.
T. Violaceum is the commonest cause od Tinea Capitis in India.
Ref: Pediatric Primary Care: Child Care, By Raymond C. Baker, Pages 30-31; Clinical Pediatric Dermatology, By Thappa – Elsevier India 2009.
Q. 2
Athlete’s foot infection is caused due to:
| A | Trichophyton | |
| B | Candida | |
| C | Papilloma virus | |
| D | E.coli |
Q. 2
Athlete’s foot infection is caused due to:
| A | Trichophyton | |
| B | Candida | |
| C | Papilloma virus | |
| D | E.coli |
Explanation:
Athlete’s foot is a health hazard associated with contact with contaminated swimming pool water. It is caused by Epidermophyton or Trichophyton species.
Q. 3
Dermatophytes infecting-
| A | Subcutaneous tissue | |
| B | Systemic organs | |
| C | Nails, hair and skin | |
| D | Superficial skin and deep tissue |
Q. 3
Dermatophytes infecting-
| A | Subcutaneous tissue | |
| B | Systemic organs | |
| C | Nails, hair and skin | |
| D | Superficial skin and deep tissue |
Explanation:
Ans. is ‘c’ i.e., Nails, hair and skin
DERMATOPHYTES
. Filamentous fungi that infect only superficial keratinized tissues – skin, hair and nails.
. Cause a variety of clinical conditions, collectively known as dermatophytoses, tinea or ring worm.
. Have been classified into three genera:
– Trichophyton – Microsporum
– Epidermophyton
. In lesions appear as :
– Hyphae
– Arthrospores
. In culture on sabouraud’s agar form :
– Septate hyphae
– Asexual spores (micro and macroconidia)
. Differentiation is based mainly on macroconidia.
|
|
Trichophyton |
Microsporum |
Epidermophyton |
|
Site |
Hair, skin and nail |
Hair and skin |
Skin and nail |
|
Microconidia |
Abundant, arranged in clusters along hyphae |
Single (multicellular) |
Absent |
|
Macroconidia |
Relatively scanty, elongated with blunt ends –> Pencil or cylindrical shaped |
Single (multicellular), Spindle shaped |
. Groups of 2 or 3 . Club shaped or pear shaped |
Q. 4
A patient made a self-diagnosis of athlete’s foot (tinea pedis) and began using a product advertised on television. The condition improved but did not clear and then the patient showed himself to a Dermatologist. A skin scraping was sent to the laboratory for culture, including culture for fungi. The fungal culture yielded a slow growing colony, which produced a few small microconidia. This is consistent with isolation of a dermatophyte of the genera –
| A | Trichophyton | |
| B | Microsporum | |
| C | Epidermophyton | |
| D | Trichosporon |
Q. 4
A patient made a self-diagnosis of athlete’s foot (tinea pedis) and began using a product advertised on television. The condition improved but did not clear and then the patient showed himself to a Dermatologist. A skin scraping was sent to the laboratory for culture, including culture for fungi. The fungal culture yielded a slow growing colony, which produced a few small microconidia. This is consistent with isolation of a dermatophyte of the genera –
| A | Trichophyton | |
| B | Microsporum | |
| C | Epidermophyton | |
| D | Trichosporon |
Explanation:
Ans. is ‘a’ i.e., Trichophyton
. Dermatophytes can be identified by their colonial appearance and microscopic morphology after growth for 2 weeks at 25°c on sabouraud’s dextrose agar.
. Differential diagnosis of Dermatophytes on the basis of Macroconidia and microconidia
|
General |
Microconidia |
Macroconidia |
|
Trichophyton |
Abundant microconidia, arranged in clusters along hyphae |
Relatively scanty, elongated with blunt ends |
|
Microsporum |
Single microconidia (multicellular) |
Single macroconidia (multicellular) |
|
Epidermophyton |
No microcondia |
Macroconidia in groups of 2 or 3 |
Q. 5
T. capitis (endothrix) is caused by –
| A | Epidermophyton | |
| B | T.tonsurans | |
| C | T.violaceum | |
| D | b and c |
Q. 5
T. capitis (endothrix) is caused by –
| A | Epidermophyton | |
| B | T.tonsurans | |
| C | T.violaceum | |
| D | b and c |
Explanation:
Ans. is ‘b’ i.e., T. tonsurans; ‘c’ i.e., T. violaceum
Two types of hair infection may occur :
- Ectothrix —> Arthrospores are produced in a sheath surrounding the hair.
- Endothrix —> Arthrospores are inside the hair shaft.
Hair infection
|
Ectothrix Endothrix . M. audouinii . T. tonsurans . M. canis . T.violaceum . T. mentagrophytes . T. schoenleinii |
|
Q. 6
Which of the following does not produces dermatophytosis in India –
| A | Trichophyton rubrum | |
| B | Trichophyton mentagrophytes | |
| C | Microsporidium distortum | |
| D | Epidermophyton floccosum |
Q. 6
Which of the following does not produces dermatophytosis in India –
| A | Trichophyton rubrum | |
| B | Trichophyton mentagrophytes | |
| C | Microsporidium distortum | |
| D | Epidermophyton floccosum |
Explanation:
Ans. is ‘c’ i.e., Microsporidium distortum
|
Skin disease
|
Dermatophvtes most commonly responsible T. rubrum, T. montagrophytes, E.floccosum. T.rubrum, E.floccosum See previous explanations T.mentagrophytes |
Important dermatophyte pathogens of man
|
Worldwide distribution Worldwide distribution Worldwide distribution Europe and America |
Important dermatophyte pathogens of animal
M. distortum –> Australia, USA
M. canis —> Worldwide
M. nanum –> Worldwide
T. equinum –> Worldwide
T. verrucosum –> Worldwide
T. simii –> India
Coming back to question
T. rubrum, T. mentographytes and E. floccosum have world wide distribution (including India), while M. distortum is found in Australia & USA.
Q. 7
Dermatophytoses in caused by –
| A | Herpes simplex | |
| B | Papilloma virus | |
| C | Trichophyton | |
| D | Candida |
Q. 7
Dermatophytoses in caused by –
| A | Herpes simplex | |
| B | Papilloma virus | |
| C | Trichophyton | |
| D | Candida |
Explanation:
Ans. is ‘c’ i.e., Trichophyton
Q. 8
The causative agent of Favus is –
| A | Microsporum audounii | |
| B | Microsporum canis | |
| C | Trichophyton mentagrophyte | |
| D | Trichophyton schoenleinii |
Q. 8
The causative agent of Favus is –
| A | Microsporum audounii | |
| B | Microsporum canis | |
| C | Trichophyton mentagrophyte | |
| D | Trichophyton schoenleinii |
Explanation:
Ans. is ‘d’ i.e., Trichophyton schoenleinii
Q. 9
Which does not cause Tinea Capitis
| A | Epidermophyton | |
| B | Microsporum | |
| C | Trichophyton Rubrum | |
| D | Trichophyton Violaceum/Schoenleinii |
Q. 9
Which does not cause Tinea Capitis
| A | Epidermophyton | |
| B | Microsporum | |
| C | Trichophyton Rubrum | |
| D | Trichophyton Violaceum/Schoenleinii |
Explanation:
A i.e. Epidermophyton
Q. 10
Most common organisim causing T. capitis is
| A | Trichophyton tonsurans | |
| B | Microsporum | |
| C | Epidermophyton | |
| D | Candida albicans |
Q. 10
Most common organisim causing T. capitis is
| A | Trichophyton tonsurans | |
| B | Microsporum | |
| C | Epidermophyton | |
| D | Candida albicans |
Explanation:
B i.e. Microsporum
Q. 11
Black dot ring worm is caused by-
| A | Microsporon | |
| B | Trichophyton | |
| C | Epidermophyton | |
| D | Candida |
Q. 11
Black dot ring worm is caused by-
| A | Microsporon | |
| B | Trichophyton | |
| C | Epidermophyton | |
| D | Candida |
Explanation:
B. i.e. Trichophyton
Q. 12
An eleven year old boy is having tinea capitis on his scalp. The most appropriate line of treatment is:
| A | Oral griseofulvin therapy | |
| B | Topical griseofulvin therapy | |
| C | Shaving of the scalp | |
| D | Selenium sulphide shampoo |
Q. 12
An eleven year old boy is having tinea capitis on his scalp. The most appropriate line of treatment is:
| A | Oral griseofulvin therapy | |
| B | Topical griseofulvin therapy | |
| C | Shaving of the scalp | |
| D | Selenium sulphide shampoo |
Explanation:
A i.e. Oral griseofulvin
Tenia capitis is most commonly caused by Microsporum canis > Trichophyton tonsurans; and never caused by Epidermophyton as it does not involve hair.
It presents with localized non-cicatrial (mostly) alopecia, itching, scaling with or without boggy swelling of scalp & easily pluckable hair.
Tinia capitis is diagnosed by potassium hydroxide (KOH) wet mounts of hair & scale and treated by griseofulvin.
Griseofulvin is used systemically only for dermatophytosis, it is ineffective topically. It is the drug of choice for treatment of tinea requiring systemic therapy. Griseofulvin has no role in treatment of Tinea versicolar & candida.
Q. 13
Grisefulvin given for the treatment of fungal infection in the fingure nail dermatophytosis for how much duration
| A | 4 weeks | |
| B | 6 weeks | |
| C | 2 months | |
| D | 3 months |
Q. 13
Grisefulvin given for the treatment of fungal infection in the fingure nail dermatophytosis for how much duration
| A | 4 weeks | |
| B | 6 weeks | |
| C | 2 months | |
| D | 3 months |
Explanation:
D i.e. 3 months
Tinea unguium is dermatophyte infection of nail plateQ. It is treated by topical ciclopiro oleamine & amorolfineQ (in cases without nail matrix involvement) and/or oral terbinafine, itraconazole, fluconazole and griseofulvinQ (in cases with nail matrix involvement).
Q. 14
About dermatophytes all are true execpt
| A | Candida albicans usually cause systemic infection | |
| B | Dermatophytes involve superficial layers of skin | |
| C | Microsporum doesn’t involve nail | |
| D | Epidermophyte doesn’t involve hair |
Q. 14
About dermatophytes all are true execpt
| A | Candida albicans usually cause systemic infection | |
| B | Dermatophytes involve superficial layers of skin | |
| C | Microsporum doesn’t involve nail | |
| D | Epidermophyte doesn’t involve hair |
Explanation:
A i.e. Candida albicans usually cause systemic infection
Candidiasis may present as buccal creamy curd like pseudomembrane (thrush) or thickness, erosion & discoloration of web space (erosio interdigitalis blastomycetica)Q. It is most common fungal infection of female genital tract. Amphotericin B is drug of choice in systemic candidiasisQ.
Q. 15
Dermatophytes can affect:
March 2012
| A | Hair | |
| B | Nail | |
| C | Scalp | |
| D | All of the above |
Q. 15
Dermatophytes can affect:
March 2012
| A | Hair | |
| B | Nail | |
| C | Scalp | |
| D | All of the above |
Explanation:
Ans: D i.e. All of the above
Three genera of dermatophytes infect skin and appendages:
Trichophyton (skin, hairs and nails), Microsporum (skin and hairs) and Epidermophyton (skin and nails)
Q. 16
Tinea corporis is commonly caused by all the following except ‑
| A | T. rubrum | |
| B | T. verrucosum | |
| C |
E. floccosum |
|
| D |
M. canis |
Q. 16
Tinea corporis is commonly caused by all the following except ‑
| A | T. rubrum | |
| B | T. verrucosum | |
| C |
E. floccosum |
|
| D |
M. canis |
Explanation:
Ans. is ‘d’ i.e., M. Canis
Q. 17
Systemic infection is caused by all fungi except ‑
| A | Cryptococcus | |
| B |
Histoplasma |
|
| C | Dermatophytes | |
| D | Paracoccidioides |
Q. 17
Systemic infection is caused by all fungi except ‑
| A | Cryptococcus | |
| B |
Histoplasma |
|
| C | Dermatophytes | |
| D | Paracoccidioides |
Explanation:
Ans. is ‘c’ i.e., Dermatophytes
