Basic Skin Biology Flashcards
Skin functions
Protection Temp regulation Sensation Vit D synthesis Immunosurveillance Cosmesis
Erythroderma complications
Total skin failure
Hypothermia
Infection
Renal failure (insensible losses)
High output cardiac failure (dilated skin vessels)
Protein malnutrition (high turnover of skin)
What is Erythroderma? Causes, symptoms, signs
> 90% body surface area affected, erythematous and exfoliated
Causes: psoriasis, eczema, drugs, cutaneous T cell lymphoma
Symptoms: pruritus, fatigue, anorexia, feeling cold
Signs: erythematous, thickened, inflamed, scaly, no sparing
4 cells of the epidermis and functions
Keratinocytes- proteins barrier
Langerhan cells - antigen presenting cells
Melanocytes - produce melanin pigment protect nuclei UV
Merkel cells - specialised nerve endings for sensation
4 layers of epidermis
(Dermis)
Deepest: Stratum basale Stratum spinosum Stratum granulosum Stratum corneum
Horny layer- most superficial
Stratum Lucidum - areas of thicker skin e.g. palms and soles
What is the dermis composed of?
Collagen, elastin, glycosaminoglycans
- strength and elasticity
+ immune cells, nerve cells, skin appendages, lymphatics, BVs
What are sebaceous glands?
Produce serum through hair follicles = pilosebaceous unit
Active after puberty
Lubricates
Androgen-> dihydrotesosterone stimulates
Increased in acne vulagris
Eccrine and apocrine glands
Regulate body temp
Sympathetic innervated
Eccrine widespread
Apocrine active after puberty, found in axillae, areolae, genitalia, anus
3 types of hair
Lanugo
Vellum (short, all over body)
Terminal (coarse long hair)
3 phases of hair follicle growth cycle
Anagen
Catagen
Telogen
Pathology of epidermidis May lead to what?
Change in:
- epidermal turnover
- surface of skin
- pigmentation of skin
What is dermatitis?
Group inflammatory conditions, affects epidermis
Eczema used interchangeably
Acute - rapidly evolving red rash may blister/ swell
In between - subacute
Chronic - long-standing irritable, darker, lichenified, scratched
1/5 ppl affected
Psychological stressors can aggregate
See slide 2
Types of dermatitis
Atopic - children, inherited factors, FH
Irritant contact- provoked by body fluids, water, detergents, solvents, harsh chemicals, friction
Allergic contact - skin contact substances: nickel, perfume, rubber, hair dye, preservatives
Dry skin - lower legs, asteatotic dermatitis/ eczema craquele
Nummular - or discoid eczema, injury set off, scattered coin shaped irritable patches last few months
Seborrhoeic dermatitis and dandruff - irritant from toxic substances produced by malassezia yeasts live on scalp/ face/ elsewhere
Infective - provoked by impetigo (bacterial infection) or fungal infection
Gravitational dermatitis - lower legs, elderly swelling, poorly functioning leg veins
Otitis externa - external ear canal
Meyerson naevus- affecting melanocytic naevi (moles)
Treatment of dermatitis
- tackle contributing factor
- bathing reduction, lukewarm, shower better, soap free cleanser
- Clothing smooth cool, coarse fibres avoided
- irritants protect from Incontinence/ dust/ water/ solvents/ detergents/ injury
- emollients liberally and often
- topical steroids 5-15day course
- pimecrolimus cream anti-inflammatory
- antibiotics (flucloxacillin/ erythromycin) often staphylococcus aureus/ streptococcus pyogenes
- antihistamines
- systemic steroids, methotrexate, azathiporine, phototherapy
What is psoriasis? Who does it affect?
Chronic inflammatory skin condition, clearly defined, red, scalp plaques (thickened skin)
Peak onset 15-25yrs and 50-60yrs fluctuates lifelong, Caucasians more, FH
See slide 3
Causes of psoriasis
Multifactorial - immune mediated
Genetic
Immune factors
Inflammatory cytokines
Release cytokines IL17A
Clinical features of psoriasis
Symmetrical Red Scaly plaques Well defined Silvery white Scalp/ elbow/ knees Mostly mild Scratching Lichenification Painful skin cracks or fissures
Types of psoriasis
Post streptococcal acute guttate psoriasis
Small plaque
Chronic plaque
Unstable plaque
Flexural
Scalp
Sebopsoriasis
Palmoplantar
Nail
erythrodermic
Aggravating factors of psoriasis
Streptococcal tonsillitis Injuries Sun exposure Obesity Smoking Alcohol Stress
Treatment of psoriasis
General - avoid smoking, alcohol, optimal weight
Topical - emollients, coal tar preparations, dithranol, salicylic acid, VD analogue, topical corticosteroids
Phototherapy
Systemic - methotrexate, ciclosporin, acitretin
What is acne vulagris? Who gets it?
Vulagris = common spots/ pimples/ zits
Adolescents, can start 8, more severe adulthood
See slide 4
Clinical features acne vulgaris
Face, spread neck/ chest/ back
Individual lesions centred pilosebaceous unit, inflamed papules, pustules, nodules, non inflamed comedones, pseudocysts
Open comedons = back heads
Closed = white heads
Treatment for acne vulagris
Depends on age/ sex/ extent
- topical anti-acne preparations, lasers, lights
- moderate add acne antibiotics (tetracyclines &/or antiandrogens)
- severe course oral isotretinoin
