derm 2 Flashcards
- Give 6 of the functions of the hair
Protection against external factors
Sebum Apocrine sweat Thermoregulation Social and sexual interaction Epithelial and melanocyte
- What are the two types of hair?
Terminal hair → Scalp, eyebrows and eyelashes
Vellus hairs → Rest of body except for: palms, soles, mucosal regions of lips and external genitalia
- What are the 3 steps of the hair cycle and what happens in each of them?
Anagen - whwere new hair forms and grows
- 85% of hair; lasts 2-6 years Catagen - regressing phase - 1% of hair; lasts 3 weeks Telogen - resting phase - 10-15% of hair; lasts 3 months
- What is the pilosebaceous unit also known as?
- What is the function of the Arrector Pili?
- Where do the holocrine sebaceous glands open up into?
Hair follicle
Contracts to make the hair erect on the skin to generate heat The pilary canal → in axillae
- Where are apocrine glands found?
- What is the uppermost portion of the hair follicle called?
- What is the lower portion of the hair follicle called?
In the skin are in the armpits, the groin, and the area around the nipples of the breast
Infundibulum - extends from opening of sebaceous gland to surface of the skin Isthmus - Between opening of sebaceous gland and insertion of arrector pili muscle
- What is meant by keratinization?
- What does keratinization begin with?
- What is found in the Bulge of the hair?
The cytoplasmic events that take place in keratinocytes that move through the different layers of the epidermis to finally differentiate to corneocytes
epithelial keratinization begins with a lack of granular layer named trichilemmal keratinization
Hair follicle stem cells
- Where and in what manner do these hair stem cells migrate?
Downward → generate the new lower anagen hair follicle → enter hair bulb matrrix, proliferate and undergo terminal differentiation to form hair shaft and inner root sheath
Upwards (distally) - form sebaceous glands and to proliferate in response to wounding
what is the bulb of the hair follicle
what is the outer root sheath
what is the inner root sheath
lowermost portion of the hair follicle
includes hair matrix and follicular dermal papilla
extends along hair bulb to infundibulum and epidermis
serves as a reservoir of stem cells
guides/ shapes hair
encloses follicular dermal papilla , nerve fiber, a capillary root and mucopolysaccharide- rich stroma
- Give 5 of the functions of the nails
Protection of underlying distal phalanx
Counterpressure effect to pulp important for walking and tactile sensation Increase dexterity / manipulation of small objects Enhance sensory discrimination Facilitate scratching or grooming
- Where does the nail plate emerge from?
- How fast does a nail grow?
- Where does the nail plate detach?
- What is the nail plate
Proximal nail fold
1-3mm/month Hyponychium
Final product of the differentiation of the nail matrix keratinocytes
- Where is the nail matrix found?
- What is the only visible portion of the nail matrix called?
- What occurs in the nail matrix?
Under proximal nail fold, above bone of distal phalanx- connected to it by tendon
Lunula Karatinocytes differentiate → lose their nuclei and are strictly adherent - cytoplasm completely filled by hard keratins. also contains melanocytes
- Is polygenic predisposition enough to contract Psoriasis?
- What is the most common form of Psoriasis characterised by?
- What are the common sites of involvement with Psoriasis?
No, environmental triggers are also needed
Sharply demarcated, scaly, erythematous plaques Scalp, elbows and knees, followed by nails, hands, feet and trunk
- What is the most common systemic manifestation of Psoriasis?
Psoriatic arthritis- psoriasis in nail matrix can lead to arthritis as nail bed is connected to distal phalange by a tendon
- Why do scales form on the skin during Psoriasis?
- Why do you not see these same scales in Flexural Psoriasis?
The keratin differentiation process occurs so quickly due to increased kearatin proliferation that they do not differentiate correctly
The friction rubs it away as these tend to be in areas whereskin touches skin eg the genitalia
- Explain the pathophysiology of Psoriasis
Stressed keratinocytes release DNA/RNA which form complex with antimicrobial peptides (endogenous antibiotic - Psoriasin)
Induces release of cytokines - TNF-alpha, IL-1 and IFN-alpha This activates dermal dendritic cells (dDCs) dDcs migrate to the lymph nodes and promote Th1, Th17, Th22 cells These release chemokines which cause the migration of inflammatory cells into the dermis These inflammatory cells cause release of cytokines which lead to keratinocyte proliferation This leads to a psoriatic plaque
- Name three features seen in Nail Psoriasis?
Subungal hyperkeratosis - scaling of the nail coming from the nail matrix
Onycholysis - nail lifts of nail bed
Pitting - Keratinocytes forming the nail plate are inflamed and not sticking to the other keratinocytes effectively- holes in nail bed
- When can the term ‘erythroderma’ be used to describe someone’s condition?
- What type of infection does Guttate Psoriasis typically follow?
When 90% or more of their skin is inflamed- functions of skin start to fail eg thermoregulation, barrier, immunological
Streptococcal throat infection
- What is meant by secondary prevention of a condition?
- Give examples of some of these aggrevating fators that might aggravate Psoriasis
- What co-morbidities might Psoriasis increase your risk of contracting?
Minimisation or avoidance of the aggravating factors
Smoking and Alcohol consumption Psoriatic Arthritis, Coronary Artery disease, Inflammatory Bone disease
- Give an example of a type of treatment that is used to treat both inflammatory bowel disease and psoriasis?
- What are some of the 1st line treatments considered when treating Psoriasis?
Anti-TNF biologic treatments
Topical gels, creams, ointments and foams or phototherapy
- What are some of the topical therapies that are used?
Vitamin D analgoues - calcipotriol
Topical coritcosteroids Retinioids - Vitamin A analogues Topical tacrolimus - T-cell inhibitors
- What does phototherapy do?
- Why might phototherapy be considered over topical therapies?
Induces T-Cell apoptosis
Cream cannot be constantly applied all over the body and so when the psoriasis covers more than 20% of the body's surface area, phototherapy is used
- Why would you be less likely to use PUVA over UVB?
- Is it the 2nd or 3rd line treatments that are systemic?
UVB does not cause an increased risk of skin cancer, whereas PUVA does
Both
- What is Acitretin and why would it be used as a treatment for Psoriasis?
Oral retinoid - Vitamin A analogue
Retinoids help bring order to the differentiation of the keratinocytes from deep to superficial Therefore it restores order of keratinization
- Give 2 examples of immunosuppresive drugs ?
- What does Apremilast do?
Methotrexate, Ciclosporin
It is a Phosphodiesterase inhibitor and this allows reduction in the amount of TNF alpha
