dermatology Flashcards
skin function
Provides an anatomical barrier
Main method of Heat Regulation
Sensory input from the body
Storage for lipids and water
Drug absorbtion and waste excretion
Commensal flora
Normal colonisation that inhibits
pathogens in healthy hosts
Mainly Bacteria and Fungi
Staphylocci and Candida
oily skin
More secretion from sebaceous glands (Sebum)
More bacterial colonisation
Skin becomes heavier & thicker
More risk of pore blockage
More ‘spots & pimples’
Less likely to wrinkle and ageing?
blackheads = comedones
Feature of Acne Vulgaris
Build up of keratin & sebum
Block pores and oxidise giving ‘black’
appearance
furuncles
Infection of skin – pockets filled with pus
Furuncles grouped together are ‘carbuncles’
Folliculitis is furuncle in a hair follicle
Organism “Staphylococcus Aureus”
Red, painful and swollen
Drain pus -
acne
Usually a term for lesions arising from
comedones
papules
pustules
nodules and
inflammatory cysts.
Usually in cosmetically sensitive areas
Follicular sensitivity to testosterone
Increase around puberty
Build up of comedones
Propionibacterium acnes overgrows
and leads to infection & cysts
Scars can form if cysts rupture
Made worse by
Some contraceptive pills (progestogen)
Greasy skin cleansers
Systemic steroid treatment
Some anticonvulsant drugs
Squeezing the spots!
Local management
Reduce excess skin oil
Cleansers – gentle soap
Antibacterial agents
Benzoyl peroxide
Retinoids
Antibiotic lotions
If local treatments fail
Antibiotics
Tetracycline based (minocyclin)
Retinoids
Isotretinoin
Hormone manipulation
Anti-androgens (cyproterone)
erysipelas
Streptoccus pyogenes
Defined sharp raised border
May blister and peel
Usually systemic symptoms
Fever
Rigors
Manage with SYSTEMIC antibiotics
Oral or sometimes IV
Can progress to
Necrotising fasciitis - death of fascial tissues
Septic shock
impetigo
Highly infections skin disease
Staphylococcal or Streptococcal
Crusty red blister appearance
Often associated with Eczema
Treated with topical antibiotics
Sometimes systemic antibiotics
Antibiotic choice found from culture
viral skin infections
Herpes Simplex
Shingles
Molluscum Contagiosum
Warts
Measles
Rubella
Fifth Disease
Roseola
Hand, Foot & Mouth
HIV
Kaposi’s Sarcoma
herpes virus infections
Herpes Simplex
Perioral or Genital
Shingles
Herpes zoster
Roseola
HHV6
Kaposi’s sarcoma
HHV8
herpex simplex
Affect single dermatome or adjacent
dermatomes
Activated by ‘trauma’
Physical, chemical, UV light, ‘run down’
Treat with Aciclovir
herpes zoster
Recurrent’ HZV
Affects SINGLE DERMATOME
Causes SIGNIFICANT pain
Neural inflammation from virus in the nerve
Pain may persist after rash has gone
Post herpetic neuralgia
Treat with HIGH DOSE Aciclovir
mollusc contagiousim
Caused by MCV – a pox virus
Resolve spontaneously in 1-2 years
Usually infants and small children
Clusters of small papules
Warm, moist areas
1-6mm size
More troublesome in children with atopic
eczema
Extensive in adults if HIV infection
warts
Human Papilloma Virus (HPV)
Types 1-3 cause most warts
Types 16 & 18 cause cervical cancer
Contact spread
Treat by
Keratolysis
Cryosurgery
Excision
If Immune competent then most resolve
spontaneously
skin infections
Fungal - dermatophytes
Athlete’s foot (tinea pedis)
Nail infections (onycholysis)
Ringworm
Intertrigo
Pityriasis versicolor
athletes foot
Typically affect feet between toes
groin involvement also common
Usually mixed fungal and bacterial infection
Scaling & sogginess of the skin
Prevent by keeping skin clean dry and damage free
Treat with antifungal/antibacterial cream
miconazole
onycholysis
Nail bed fungal infection
Usually Tinea unguium infection
Nail becomes malformed, thick and
crumbly
May be seen with athlete’s foot
ringworm
Can affect different parts of the body
Groin – tinea cruris
Often spread from feet
Body – tinea corporis
Can be caught from infected animals
Scalp – tinea capitis
Inflammation of scalp leading to hair loss
Mainly in young children
intertrigo
Fungal infection due to chafing in moist
body folds:
Under breasts
Armpits
Inner thighs
Treat with topical
antifungal cream:
Clotrimazole
or Miconazole
pityriasis versicolor
Caused by Pityrosporum orbiculare
Usually a harmless commensal
Also involved in ‘cradle cap’
Excessive growth causes the condition
Results in patchy skin pigmentation
Pale red or brownish
Treat with topical or systemic antifungal
Topical ketoconazole (in wash or shampoo)
Systemic Itraconazole
skin infestations
scabies
lice
scabies
Infection with the ‘Scabies Mite’
Sarcoptes scabiei
From contact with an infected individual
(skin-to-skin)
Occasionally from bedding
Usually 10-12 mites infect the host
3 eggs a day for life of mite – up to 2 months
Burrows appear on the skin
Folds between fingers & on wrists
ITCH is often most troublesome feature
More severe at night
On trunk and limbs
RASH appears on trunk and limbs
Tiny red intensely itchy bumps
May get secondary impetigo
Rash and Itch are ALLERGY and can persist long
after the infestation is gone
Use chemical insecticides – Scabicides
Benzyl benzoate
Permethrin
Malathion
Apply to the WHOLE body from the chin
down including under the nails
Treat ALL close contacts whether obviously
infected or not
lice
Three types
Head
Pubic
Body
Transmitted by close contact with an
infected individual
Transmitted by shared items
Clothing combs, bedding, brushes and toilet
seats!
Head lice most commonly affect
children
Can spread to rest of family though!
Look for ‘nits’ – eggs cemented to the
hair near the scalp
Need to go through hair with a ‘fine
toothed comb’!
NOT hygiene related
Body lice treated by personal and
clothing hygiene
Hot water washing and drying
Chemical Insecticides
Permethrin
Malathion
Phenothrin
inflammatory skin disease
eczema
occupational dermatitis
psoriasis
eczema
Inflammation of the skin
Becomes itchy, dry, flaky
Occasionally weeps
2 main types
atopic & contact
Usually affect FLEXOR surfaces of skin or trunk
atopic eczema
Commonest form
Develops in childhood
Usually improves with age
Tends to run in families
Associated with other ‘atopic’ conditions
Hay fever, asthma
other eczema
Contact - most likely for adult onset
Contact with allergen = perfumes, detergents, soaps
Seborrhoeic – scalp & eye lashes
Appears as severe form of dandruff
Discoid – circular patches on the body
Gravitational – related to poor circulation in legs
Triggers?
Some find stress, menstruation, illness,
changes in the weather
Management
Cotton clothing
Emollients
Soap substitutes
Corticosteroids – usually topical
eczema management
Emollients
Oily and prevent drying of the irritated
skin
Apply after bathing to trap moisture
Corticosteroid
Remove the inflammation and allow skin
to return to normal
occupational contact dermatitis
Reaction to an environmental agent
Usually results in an rash
May blister or get urticarial swelling
Can be immediate or up to 72hrs after
exposure
Usually an intense itch
Treatment = remove source
Problem is identifying source
Topical steroid can help
psoriasis
Inflammatory skin disease – 2% pop
Cause unknown
Dysregulated epidermal proliferation = new cells produced faster than old cells lost
Skin surface builds up & thickens
EXTENSOR surfaces of limbs & trunk
Can be associated with a severe form of arthritis – psoriatic arthropathy
Red scaly patches – can itch
Can run in families
psoriasis - treatment
No one clear treatment – initially topical
Emollients
Topical steroids
Tar
Dithranol
Vitamin A derivatives
PUVA – psoralen uv light A
Topical drug, activated by UV light
psoriasis systemic treatment
Drugs to reduce cell turnover
Methotrexate
Ciclosporin
Aitretin
Infliximab
Etanercept
immunological skin diseases
ATTACKING PROTEINS IN SKIN
Blistering Conditions
Pemphigoid
Pemphigus
Epidermolysis bullosa
Lichen Planus
Connective Tissue diseases
Scleroderma
Dermatomyositis
Raynauds
Skin and oral/genital mucosa share many common
antigens and epitopes
Many blistering skin conditions also affect the mouth
Auto-antibody attack on skin
components causing loss of cell-cell
adhesion
‘Split’ forms in skin
Fills with inflammatory exudate
Forms vesicle/blister
blistering conditions vesiculobullous diseases
Pemphigoid
Pemphigus
Epidermolysis Bullosa
Linear IgA Disease
Dermatitis Herpetiformis
pemphigoid
SUB epithelial antibody attack
Thick walled blisters (full epidermis)
Usually persist to be seen
Clear or blood filled blisters
Different forms and presentations
Bullous Pemphigoid
Mucous Membrane Pemphigoid
Cicatritial Pemphigoid
Oral & Skin Lesions
Both can cause lesions in either place
Bullous usually skin
Mucous Membrane usually mouth/eye/genital
Scarring a feature in some cases
Manage with immunosuppresants
Steroids
‘steroid sparing’ drugs
pemphigus
Vulgaris
Affects mucosa and skin
Usually oral lesions before skin
RARELY see intact bullae
Intra-epithelial blister
Surface easily lost
Fatal disease without treatment
Now often complications of the treatment are major cause of death
epidermolysis bullosa
Group of conditions
Some very mild – may appear later in
life
Some incompatible with life – death
in-utero or shortly after birth
Genetically determined
Severity determined by epitopes involved
Scarring determined by epitopes involved
EB Simplex
Junctional EB
Dystrophic EB
EB Acquisita *
Problems
Infection
Fluid loss
Scarring
