DERM Flashcards
Functions of the skin
1. Barrie rot infection 2> thermoregulation 3. Protection against trauma 4. Protection against UV 5. Vit D syntehsis 6. Regulate H20 loss
pH of the skin
5.5
Why is the skin pH 5.5
Allows proteases on the skin to do desquamination
What is the stratum corneum
Made of corner-desmosomes and desmosomes
What are cornel-desmosomes
Adhesion molecules that keep corneocytes together
Describe the layers of the skin
- Stratum lucidium
- Granulosum
- Spinous
- Basale
What nerve endings are found in the dermis
Meissner’s corpuscules - light touch
2. Pacinian corpuscle (vibration)
Role of keratinocytes
Produce keratin as a protective barrier
Role of Langerhans cells
Present antigens and activate T cells
Role of merkel cells
Specialised nerve endings for sensation
Common causes of itch with rash
- URTICARIA (hives)
- ATOPIC ECZMA
- Psoriasis
- Scabies
Common causes of itch with no rash
- Renal failure
- Jaundice
- Iron deficiency
- Lymphoma (hodgkin’s)
- Polycythaemia
- Pregnancy
- Drugs
- Diabetes
- Cholestasis
What is acne
Expansion and blockage of hair follicle and inflammation
Most common variant of acne
Acne Vulgaris
Pathophysiology of acne
- Hypercornfiictaion causes narrowing of hair follicle
- Increased sebum production
- Sebum is trapped which narrows follicle further
- Sebum stagnates at pit of follicle where there is no oxygen
- Anaerobic conditions allow propionibacterium acne to multiply
- P. acne breaks down triglycerides in sebum into free fatty acids = irritation, inflammation and attraction of neutrophils
- Pus formation as attract neutrophils come into the area
Whitehead vs blackhead
White - closed comedones
Black - open comedones
Clinical presentation of acne
- Whiteheads
- Blackheads
- Skin coloured papule (red spots)
- Inflammatory lesions when closed wall of comedones rupture
- Pustules (yellow spots)
- Nodules (large red bumps
Diagnosis of acne
- Skin swabs for culture
2. Hormonal test in females
Treatment of acne
- BENZOYL PEROXIDE
- CLINDAMYCIN GEL
- TAZAROTENE GEL (topical retinoid)
How does Benzoyl peroxide work
Increases skin turnover
Clears pores and reduces bacterial count
Causes dryness due to kertaolytic effect
How do topical retinoids work
Inhibit formation and reduce number of micromedones
Severe acne treatment
- ORAL DOXYCYCLINE
- ORAL MINOCYCLINE
HORMONE TREATMENT with ORAL CO-CYPRINDIOL (anti-androgen suppresses sebum productioN)
What is eczema/dermatitis
Breakdown of skin due to thinning of stratum corneum - increased risk of inflammation
What is endogenous eczema
Hypersensitivity caused (food allergies)