- 1. Dermatophytes
- 2. Yeast & Yeast like Fungus Cryptococcus, Candida, Pneumocystii carinii
- 3. Aspergillus & Mucormycosis
- 4. Dimorphic Fungi
- Filamentous fungi (Mold) that infect only superficial keratinized tissues – skin, hair and nail.
- Causative agent of Ringworm or Tinea or Dermatophytoses.
- Not involve living Tissues.
- It has 3 genera – Trichophyton, Microsporum, Epidermophyton.
- In lesion, it form hyphae and arthospores.
- In culture it form septate hyphae and asexual spores (micro and macroconidia) with powdery and pigmented colonies.
- They are differentiated mainly by nature of macrocondia.
Clinical features
- Local inflammation is due to irritation by fungal products and hypersensitivity reaction.
- Transmission occurs from infected to uninfected person often by brushes, combs and towels.FeaturesTrichophytonMicrosporumEpidermophytonSiteInfect hair, skin and nailHair and skin onlySkin and Nail onlyColonyPowdery, pigmentedCotton like pigmentedPowdery greenish yellowSpores
- Microconidia
AbundantRelatively scantyAbsent- Macroconidia
Pencil or Cylindrical shaped, relatively scantyMulticellular Spindle or fusiform shaped and is predominant sporeClub shaped or pear shaped multicellular - Clinically ringworm is classified depending on the site involved eg. Tinea capitis infect scalp and hair.
- MC species infecting human being – T. rubrum.
QUESTIONS
1. T. capitis (endothrix) is caused by :
[PGI 00]
- Epidermophyton
- T. tonsurans
- T. violaceum
- Microsporum
2. Kerion is caused by :
[PGI 98]
- Candida
- Streptococcus
- Dermatophytes
- Herpes
3. Tinea cruris is caused by :
[PGI 97]
- Epidermophyton
- Trichophyton
- Microsporum
- Candida
1. b and c | 2. c) Dermatophytes | 3. a and b |
EXPLANATIONS AND REFERENCES WITH ILLUSTRATIVE ANSWERS
1. Ans. is b and c i.e. T. tonsurans; and T. violaceum
Ref. Ananthnarayan 7/e, p 616
Dermatophytoses | Common causative agents |
---|---|
Tinea captis | Microsporum, Trichophyton most species |
Favus | T. schoenleinii T. violaceum, M. gypseum |
Tinea barbae | T. rubrum, T.mentagrophytes, T. verrucosum |
Tinea imbricata | T. concentricum |
Tinea corporis | T. rubrum and any other dermatophyte |
T. cruris | E. floccosum, T. rubrum |
T pedis | T. rubrum, E. floccosum |
Ectothrix hair infection | Microsporum species, T. rubrum |
Endothrix hair infection | T. schoenleinii, T. tonsurans, T. violaceum |
2. Ans. is c i.e. Dermatophytes
Ref. Dashore Manual of Skin, p 26
Kerion
- The fungal infection of scalp caused by microsporum or trichophyton species not by epidermophyton.
- Inflammatory boggy swelling covering small or large areas of scalp in which hair are loose and fallout or can be easily epilated.
- Commonly caused by zoophilic dermatophytes like T. mentagrophytes and T. verruco sum.
- Follicular scarring and partial alopecia is common after severe kerion.
Favus
- Chronic type of ringworm in which dense crusts (scutula) develop in hair follicles leading to alopecia and scarring
Remember : Both kerion and favus are type of Tinea captis.
3. Ans. is a and b i.e. Epidermophyton; and Trichophyton
Ref. Ananthnarayan 7/e, p 616
Already explained, refer answer no. 1
Chapter Review
- This section includes questions of Various Other PGMEES from 1990 – 2007.
- Questions are arranged in decreasing order of yearwiz. This is done to make referral system easier and uncomplicated to save the precious time of PGMEE Aspirant.
1. Dermatophytes are fungi infecting :
[Delhi 93]
- Subcutaneous tissues
- Systemic organs
- Nails, hair and skin
- Superficial skin and deep tissue
[Ref. Ananthnarayan 7/e, p 613]
2. Dermatophytosis is caused by :
[Delhi 02]
- Herpes simplex
- Papilloma virus
- Trichophyton
- Candida
[Ref. Ananthnarayan 7/e, p 613]
Answer
1. c) Nails, hair ... | 2. c) Trichophyton |