Podcast
Questions and Answers
What is the primary component of hair?
What is the primary component of hair?
Which of the following statements about hair is true?
Which of the following statements about hair is true?
Where do hair follicles grow from?
Where do hair follicles grow from?
What is essential for understanding hair-related conditions?
What is essential for understanding hair-related conditions?
Signup and view all the answers
Which type of cells primarily make up hair?
Which type of cells primarily make up hair?
Signup and view all the answers
What is the primary component of the hair shaft?
What is the primary component of the hair shaft?
Signup and view all the answers
In which phase of the hair growth cycle does active growth primarily occur?
In which phase of the hair growth cycle does active growth primarily occur?
Signup and view all the answers
What percentage of hairs are typically in the Catagen phase at any given time?
What percentage of hairs are typically in the Catagen phase at any given time?
Signup and view all the answers
What distinguishes scarring alopecia from non-scarring alopecia?
What distinguishes scarring alopecia from non-scarring alopecia?
Signup and view all the answers
Which of the following is a common cause of non-scarring alopecia?
Which of the following is a common cause of non-scarring alopecia?
Signup and view all the answers
What is a characteristic of Telogen Effluvium?
What is a characteristic of Telogen Effluvium?
Signup and view all the answers
During which phase does hair shedding primarily occur?
During which phase does hair shedding primarily occur?
Signup and view all the answers
Which phase of the hair growth cycle is least likely to be populated by hairs?
Which phase of the hair growth cycle is least likely to be populated by hairs?
Signup and view all the answers
What is a characteristic feature of alopecia areata?
What is a characteristic feature of alopecia areata?
Signup and view all the answers
What is a common exogenous factor that may provoke discoid lupus erythematosus (DLE)?
What is a common exogenous factor that may provoke discoid lupus erythematosus (DLE)?
Signup and view all the answers
Which immune cells are primarily involved in the pathophysiology of alopecia areata?
Which immune cells are primarily involved in the pathophysiology of alopecia areata?
Signup and view all the answers
Which area is most commonly affected by lichen planopilaris (LPP)?
Which area is most commonly affected by lichen planopilaris (LPP)?
Signup and view all the answers
What is the primary characteristic of hair loss caused by chronic bacterial infections?
What is the primary characteristic of hair loss caused by chronic bacterial infections?
Signup and view all the answers
What is thought to contribute to the autoimmune response in alopecia areata?
What is thought to contribute to the autoimmune response in alopecia areata?
Signup and view all the answers
Which of the following conditions is NOT a common cause of non-scarring alopecia?
Which of the following conditions is NOT a common cause of non-scarring alopecia?
Signup and view all the answers
Which factor is NOT considered to contribute to the pathogenesis of alopecia areata?
Which factor is NOT considered to contribute to the pathogenesis of alopecia areata?
Signup and view all the answers
What condition is primarily related to follicular hyperkeratosis and can result in scarring alopecia?
What condition is primarily related to follicular hyperkeratosis and can result in scarring alopecia?
Signup and view all the answers
Alopecia areata has a strong hereditary component due to the presence of what?
Alopecia areata has a strong hereditary component due to the presence of what?
Signup and view all the answers
What is one reason that discoid lupus erythematosus (DLE) may be found in non-sun exposed areas?
What is one reason that discoid lupus erythematosus (DLE) may be found in non-sun exposed areas?
Signup and view all the answers
What is the role of CD8+ T-lymphocytes in alopecia areata?
What is the role of CD8+ T-lymphocytes in alopecia areata?
Signup and view all the answers
What is the relationship between lichen planopilaris (LPP) and lichen planus?
What is the relationship between lichen planopilaris (LPP) and lichen planus?
Signup and view all the answers
In the pathophysiology of lichen planopilaris, what type of immune response is thought to occur?
In the pathophysiology of lichen planopilaris, what type of immune response is thought to occur?
Signup and view all the answers
Which of the following statements about alopecia areata is correct?
Which of the following statements about alopecia areata is correct?
Signup and view all the answers
Which of the following statements about discoid lupus erythematosus (DLE) is true?
Which of the following statements about discoid lupus erythematosus (DLE) is true?
Signup and view all the answers
What factor is NOT considered to affect the pathophysiology of hair loss in chronic bacterial infections?
What factor is NOT considered to affect the pathophysiology of hair loss in chronic bacterial infections?
Signup and view all the answers
In the case of folliculitis decalvans, which organism is often associated with pustular lesions?
In the case of folliculitis decalvans, which organism is often associated with pustular lesions?
Signup and view all the answers
What is the most common presentation of tinea capitis?
What is the most common presentation of tinea capitis?
Signup and view all the answers
What is a key characteristic of kerion, a manifestation of tinea capitis?
What is a key characteristic of kerion, a manifestation of tinea capitis?
Signup and view all the answers
Which dermatophyte species are primarily responsible for causing tinea capitis?
Which dermatophyte species are primarily responsible for causing tinea capitis?
Signup and view all the answers
Which condition can lead to scarring alopecia if it persists untreated?
Which condition can lead to scarring alopecia if it persists untreated?
Signup and view all the answers
What is usually the cause of folliculitis decalvans?
What is usually the cause of folliculitis decalvans?
Signup and view all the answers
How is tinea capitis most commonly contracted?
How is tinea capitis most commonly contracted?
Signup and view all the answers
What happens to hair follicles in cases of severe bacterial superinfection of chronic scalp conditions?
What happens to hair follicles in cases of severe bacterial superinfection of chronic scalp conditions?
Signup and view all the answers
In what age group does kerion most commonly appear?
In what age group does kerion most commonly appear?
Signup and view all the answers
Study Notes
Introduction to Hair Disorders
- Hair is a complex structure composed of keratinized cells that grow from follicles embedded within the skin.
Understanding Hair Anatomy
- Hair is primarily composed of dead, keratinized cells.
- A hair shaft grows within a follicle at a rate of about 1 cm per month.
- This growth is due to cell division within the hair bulb at the base of the follicle.
- The cells produce the three layers of the hair shaft (medulla, cortex, cuticle).
- The hair shaft is mainly composed of the protein keratin (which is also a major component of skin and nails).
The Hair Growth Cycle
- Hair growth follows a cycle with three main phases:
- Anagen: active growth phase (1-6 years, majority of hairs are in this phase)
- Catagen: transitional phase of 1-3 weeks when growth stops, and the follicle shrinks (1–3% of hairs)
- Telogen: resting phase for 1-4 months (up to 10% of hairs in a normal scalp)
- Exogen: shedding of the hair
Causes of Scarring and Non-Scarring Alopecia
- Hair loss (alopecia) can be an isolated problem or associated with another disease or condition.
- It can be non-scarring (temporary or reversible) or scarring (permanent), depending on the cause.
Non-Scarring Alopecia
- Hair loss with non-scarring damage to the hair follicles (hair loss is usually reversible or treatable).
- Common causes:
- Alopecia Areata
- Telogen Effluvium
- Male and female pattern hair loss
Scarring Alopecia
- Hair loss characterized by permanent damage to the hair follicles.
- Common causes:
- Discoid Lupus Erythematosus (DLE)
- Lichen Planopilaris (LPP)
- Chronic bacterial infections
- Chronic fungal infections
The Non-Scarring Alopecias in More detail
- Non-scarring alopecia is hair loss with non-scarring damage to the hair follicles.
Pathophysiology of Hair Loss in Alopecia Areata
- Alopecia Areata is an autoimmune condition resulting in hair loss, typically presenting with discrete bald patches on the scalp.
- The immune system mistakenly targets hair follicles as foreign and launches an immune response against them.
- The exact cause of this autoimmune response is not yet fully understood.
- Loss of immune privilege in anagen hair follicles is thought to play a key role.
- Genetic susceptibility is also thought to contribute.
Pathophysiology of Hair Loss in Alopecia Areata – Autoimmune Response
- CD8+ T-lymphocytes are thought to play a crucial role in alopecia areata development.
- These lymphocytes infiltrate hair follicles and recognize specific self-antigens as foreign or abnormal.
- This triggers an immune response, leading to inflammation and hair follicle damage.
Pathophysiology of Hair Loss in Alopecia Areata – Genetic and Other Factors
- Alopecia areata has a strong hereditary component. At least 16 genetic risk loci have been detected.
Pathophysiology of Discoid Lupus Erythematosus (DLE)
- DLE likely occurs in genetically predisposed individuals.
- Exogenous factors like smoking and ultraviolet radiation also play a role (DLE is a photosensitive disorder).
Pathophysiology of Hair Loss in Lichen Planopilaris (LPP)
- Lichen planopilaris is an uncommon inflammatory condition that can lead to permanent hair loss.
- It is considered a form of lichen planus affecting the hair follicles.
- It results in patchy, progressive, permanent hair loss mainly on the scalp.
- The exact cause is unknown, but it is thought to be a cytotoxic autoimmune response to an unknown antigen located in hair follicles.
- The exact trigger for this immune response is not fully understood.
- The disease may rarely be gene-related or drug-induced.
Pathophysiology of Hair Loss in Chronic Bacterial Infections
- The specific pathophysiology of hair loss in chronic bacterial infections varies depending on:
- The type of bacteria involved (e.g., staphylococcus aureus).
- The location and severity of the infection (e.g., scalp).
- Individual patient factors (e.g., underlying HIV).
- Bacterial scalp infections presenting as scalp folliculitis do not usually result in scarring hair loss.
Pathophysiology of Hair Loss in Chronic Bacterial Infections Continued
- Severe bacterial superinfection of chronic scalp conditions (e.g., seborrhoeic eczema) may result in permanent hair follicle destruction.
- Dissecting cellulitis of the scalp is a rare cause of scarring alopecia.
Pathophysiology of Hair Loss in Chronic Bacterial Infections Continued
- Folliculitis decalvans is a highly inflammatory scarring alopecia often associated with Staphylococcus aureus.
Pathophysiology of Hair Loss in Fungal Infections
- Tinea capitis is a common fungal infection of the scalp presenting with pruritic, scaling areas of non-scarring hair loss.
- Trichophyton and Microsporum species of dermatophyte fungi are the major causes.
- The infection is often contracted from another human or an animal through direct contact.
- Tinea capitis does not usually cause scarring alopecia unless the infection is long-standing, untreated, or severe.
Pathophysiology of Hair Loss in Fungal Infections - Kerion
- Kerion is a severe manifestation of tinea capitis resulting from a dramatic immune response to the infection.
- It is characterized by an inflammatory plaque with pustules, thick crusting, and/or drainage.
- Persistent kerion can lead to scarring alopecia.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz explores the complexities of hair structure and anatomy, detailing the composition and growth cycle of human hair. Participants will learn about keratin's role, the phases of the hair growth cycle, and the characteristics of each phase. Ideal for those interested in dermatology or trichology.
