Podcast
Questions and Answers
Which type of fungi is characterized by being multicellular and growing best at 25°C?
Which type of fungi is characterized by being multicellular and growing best at 25°C?
What is the clinical name for the infection caused by dermatophytes in keratinized structures?
What is the clinical name for the infection caused by dermatophytes in keratinized structures?
Which dermatophyte primarily infects humans and is transmitted between individuals?
Which dermatophyte primarily infects humans and is transmitted between individuals?
Which form of tinea corporis is typically associated with contact sports such as wrestling?
Which form of tinea corporis is typically associated with contact sports such as wrestling?
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What is a distinguishing feature of tinea corporis caused by M.canis following contact with kittens?
What is a distinguishing feature of tinea corporis caused by M.canis following contact with kittens?
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Which type of dermatophyte is usually responsible for causing tinea imbricata?
Which type of dermatophyte is usually responsible for causing tinea imbricata?
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How does the infection of dermatophytes typically progress in the skin?
How does the infection of dermatophytes typically progress in the skin?
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What impact do topical steroid applications have on tinea incognito?
What impact do topical steroid applications have on tinea incognito?
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Which investigation is primarily indicated to confirm the presence of oropharyngeal candidiasis?
Which investigation is primarily indicated to confirm the presence of oropharyngeal candidiasis?
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What is the mode of action for flucytosine in antifungal therapy?
What is the mode of action for flucytosine in antifungal therapy?
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Which of the following is a common clinical manifestation of cutaneous candidiasis?
Which of the following is a common clinical manifestation of cutaneous candidiasis?
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What should be done to manage chronic paronychia effectively?
What should be done to manage chronic paronychia effectively?
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Which antifungal drug class is known to inhibit the cytochrome P450 enzyme involved in ergosterol biosynthesis?
Which antifungal drug class is known to inhibit the cytochrome P450 enzyme involved in ergosterol biosynthesis?
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Which of the following is characterized by the presence of yellow cup-shaped crusts and is caused by T. schoenleinii?
Which of the following is characterized by the presence of yellow cup-shaped crusts and is caused by T. schoenleinii?
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Which clinical type of Tinea pedis is characterized by scaling, fissuring, or erythema between the third and fourth toes?
Which clinical type of Tinea pedis is characterized by scaling, fissuring, or erythema between the third and fourth toes?
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What is the primary cause of Tinea Pedis, also known as athlete's foot?
What is the primary cause of Tinea Pedis, also known as athlete's foot?
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What is the primary causative agent of Pityriasis (Tinea) Versicolor?
What is the primary causative agent of Pityriasis (Tinea) Versicolor?
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What is a characteristic feature of hyperkeratotic Tinea pedis?
What is a characteristic feature of hyperkeratotic Tinea pedis?
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What type of dermatophyte infection would most likely be experienced by animal handlers and is characterized by intense inflammation?
What type of dermatophyte infection would most likely be experienced by animal handlers and is characterized by intense inflammation?
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Which variant of Tinea Capitis results in partial alopecia covered with grayish-white scales?
Which variant of Tinea Capitis results in partial alopecia covered with grayish-white scales?
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Which KOH smear appearance is characteristic of Pityriasis Versicolor?
Which KOH smear appearance is characteristic of Pityriasis Versicolor?
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Which agent commonly causes superficial white onychomycosis?
Which agent commonly causes superficial white onychomycosis?
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What is the primary predisposing factor for Tinea Cruris?
What is the primary predisposing factor for Tinea Cruris?
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What is the most common site for lesions in Pityriasis Versicolor?
What is the most common site for lesions in Pityriasis Versicolor?
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What condition can result from treatment of a fungal infection with topical steroids?
What condition can result from treatment of a fungal infection with topical steroids?
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Which of the following treatments is effective against Pityriasis Versicolor?
Which of the following treatments is effective against Pityriasis Versicolor?
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Fibrous animal ringworm of the scalp can lead to which of the following complications?
Fibrous animal ringworm of the scalp can lead to which of the following complications?
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Which reaction occurs as a systemic response to fungal antigens in cases of inflammatory Tinea Capitis?
Which reaction occurs as a systemic response to fungal antigens in cases of inflammatory Tinea Capitis?
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Which investigation method is used to detect dermatophyte infections?
Which investigation method is used to detect dermatophyte infections?
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Griseofulvin is prescribed at a dosage of 12.5 mg/kg for which condition?
Griseofulvin is prescribed at a dosage of 12.5 mg/kg for which condition?
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What is the common presentation of Tinea Manuum?
What is the common presentation of Tinea Manuum?
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In which area would you differentiate erythema from tinea?
In which area would you differentiate erythema from tinea?
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What is the typical duration for systemic Terbinafine treatment in cases of tinea cruris?
What is the typical duration for systemic Terbinafine treatment in cases of tinea cruris?
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Which variant of Tinea Capitis is most often associated with dermatophytes of animal origin?
Which variant of Tinea Capitis is most often associated with dermatophytes of animal origin?
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The increase of which factors can predispose an individual to Candidiasis?
The increase of which factors can predispose an individual to Candidiasis?
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Which condition is primarily a dermatophytosis of the groin and is most common in men?
Which condition is primarily a dermatophytosis of the groin and is most common in men?
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Tinea unguium typically affects which part of the body?
Tinea unguium typically affects which part of the body?
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Which of the following conditions can masquerade as a dermatophyte infection due to misuse of treatment?
Which of the following conditions can masquerade as a dermatophyte infection due to misuse of treatment?
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Which of the following symptoms is NOT typically associated with Tinea Pedis?
Which of the following symptoms is NOT typically associated with Tinea Pedis?
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Which demographic is most likely to experience Pityriasis Versicolor?
Which demographic is most likely to experience Pityriasis Versicolor?
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What is a major identifying feature of vesiculobullous Tinea pedis?
What is a major identifying feature of vesiculobullous Tinea pedis?
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What is a common environmental condition associated with Pityriasis Versicolor?
What is a common environmental condition associated with Pityriasis Versicolor?
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Which antigungal agent is known to be effective for superficial fungal infections like Tinea?
Which antigungal agent is known to be effective for superficial fungal infections like Tinea?
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Study Notes
Fungal Skin Infections
- Fungal skin infections, also known as mycoses, are infections caused by fungi.
- Fungi are classified into three main types: unicellular yeast (37°C), multicellular mold (25°C), and dimorphic fungi (mold→yeast).
- The skin structure includes the epidermis, dermis, and subcutaneous layer. Hair follicles, sebaceous glands, and sweat glands are also found in the skin.
- Superficial mycoses infect various superficial skin structures including hair, nails, and stratum corneum. Dermatophytoses (ringworm) is a common superficial infection.
- Dermatophytes are classified as geophilic (live in soil), zoophilic (infect animals which can spread to humans), and anthropophilic (infect humans and spread person-to-person).
- Dermatophytosis (ringworm) is the infection of keratinized structures (hair, nails, stratum corneum) by dermatophytes. The three main types of dermatophytes are Trichophyton, Epidermophyton, and Microsporum
- Dermatophyte infections spread in a centrifugal pattern, creating ring-shaped lesions.
- Common clinical forms of tinea corporis include tinea capitis (scalp), tinea barbae (beard and mustache), tinea facialis (face), and tinea corporis (body), tinea cruris (groin), tinea manuum (hands), tinea pedis (feet), tinea unguium (nails), tinea incognito.
- All dermatophytes can cause lesions on glabrous skin (smooth skin). Typical lesions include annular raised edges (active border), and a clearing center, covered with papules, vesicles, and pustules.
- Tinea corporis (body ringworm) is often caused by M. canis and can be acquired from infected animals. Different clinical variants exist including circinate lesions, tinea gladiatorum, tinea imbricata, tinea incognito, and majocchi granuloma
- Tinea cruris ("jock itch") is a dermatophyte infection of the groin that involves the upper medial thigh, buttock, and pubic area. It is less common to infect the scrotum. Predisposing factors include warm, moist environments and sweating.
- Tinea capitis is a fungal infection of the scalp. It can be non-inflammatory (grey patch or black dot) or inflammatory (kerion).
- Tinea pedis (athlete's foot) is caused by T. rubrum or T. mentagrophytes, characterized by scaling, maceration, and itching between the toes, especially the fourth interdigital space. Common clinical types include interdigital, hyperkeratotic, and vesiculobullous.
- Tinea unguium (nail fungus) is a dermatophyte infection of the nails commonly caused by Trichophyton sp. It can present as distal/lateral subungual onychomycosis(nail lifts up, free end crumbles), superficial white onychomycosis(white patches on nail), and proximal white onychomycosis
Pityriasis Versicolor
- A chronic superficial fungal disease of the skin caused by lipophilic yeast Malassezia furfur and Malassezia globosa.
- Lesions are asymptomatic, small, hypopigmented or hyperpigmented macules. Common sites include back, underarm, upper arm, chest, and neck; typically seen in adolescent and young adult males
- Associated with hot and humid climates and increased sweating.
- Diagnosis involves clinical presentation, KOH mount examination ('spaghetti and meatballs'), and Wood's lamp examination (yellow-orange fluorescence).
- Treatment includes antifungal creams, lotions, or shampoos (e.g., ketoconazole, terbinafine, selenium sulfide) that are usually effective but may cause ongoing skin discoloration for weeks to months
Candidiasis
- Candidiasis of skin, mucous membranes, and nails.
- Predisposing factors include infancy, pregnancy, old age, immune disorders (e.g., leukemia), corticosteroid therapy, chemotherapy, immunosuppressive drugs, antibiotic use, and endocrine disorders (e.g., diabetes), and carcinoma.
- Common clinical forms include thrush, vulvovaginitis, intertrigo, diaper, perineal, and paronychia candidiasis.
- Diagnosis involves KOH mounts (budding yeasts , pseudohyphae), cultures, and urine sugar testing (if indicated).
- Treatment involves controlling predisposing factors (eliminating antibiotics, controlling moisture, etc.). Antifungal creams, topical drugs (e.g., nystatin), oral suspensions, or oral and topical antibitiocs are typically used, alongside specific management of each clinical form.
Investigations for Fungal Skin Infections
- Microscopic examination of skin scrapings or nail clippings, using KOH mounts
- Cultures using appropriate media
- Wood's lamp exam for specific types of infections (e.g., Pityriasis versicolor)
Antifungal Therapy
- Antifungal therapies are classified by their site of action, these types include:
- Nuclear level: Flucytosine
- Cytoplasmic membrane level: Polyenes (e.g., Nystatin, Amphotericin B), Azoles (e.g., imidazole, ketoconazole, itraconazole, fluconazole), and Allaylamines (e.g., terbinafine).
- Cell wall level: Echinocandins
- Mitotic spindle: Griseofulvin
- Various other specific antifungal therapy options are also available
Complications
- Severe ringworm infections can cause scarring alopecia on the scalp.
- Fungal infections may be problematic (epidemics) in schools, and their presentation can be masked by topical steroid use.
Differential Diagnoses
- Conditions that mimic fungal infections should be considered such as skin conditions such as seborrheic eczema, psoriasis, carbuncles, abscesses, eczema, and candidiasis, pityriasis rosea, erythrasma.
Treatment Summary
- Antifungal medications, both topical and systemic, are used to treat different types of fungal infections.
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Description
Test your knowledge on fungal infections, particularly those caused by dermatophytes. This quiz covers various aspects including characteristics, transmission, and treatment of these infections. Delve into clinical manifestations and management strategies to assess your understanding of this important topic in mycology.
