Derm- common rashes Flashcards
what is atopic dermatitis
eczema is a chronic inflammatory skin condition that causes the skin to become itchy, red, dry, and sometimes cracked or blistered
reaction pattern of eczema
spongiotic
eczema is caused by a combination of which main three factors
< skin barrier function
environmental factors
immunology
in eczema there is mutations in fillagrin gene resulting in what?
decreased AMP in skin
what is ananthosis
thickening of the epidermis
diagnostic criteria of atopic dermatitis is itching plus 3 or more of:
visible flexural rash
history of flexural rash
personal history of atopy
dry skin
age onset before 2
when does atopic dermatitis present
in childhood
what is allergic contact dermatitis
Delayed type IV allergy to an antigen
how long after exposure does reaction occur in allergic contact dermatitis
24-48 hours after exposure
investigation for allergic contact dermatitis
patch test- allergen on finn chambers, applied on back, removed after 48 hours, readings at 48 and 96 hours
what is irritant contact dermatitis
Eczema due to contact with an irritant
secondary infection- crusting in eczema indicates which causative agent?
Staph. aureus impetigo
secondary infection- Monomorphic punched-out lesions indicates which causative agent?
Herpes simplex virus- eczema herpeticum
what is psoriasis
chronic autoimmune disorder characterised by well-demarcated, erythematous, scaly plaques
what are the two age peaks in psoriasis incidences
20s
50s
Precipitating factors for psoriasis
stress
trauma
alcohol and smoking
infection- strep throat
drugs- beta blockers, lithium, antimalarial drugs
common sites for psoriasis
scalp
elbows
knees
systemic therapy in psoriasis
eg methotrexate, biologics
Guttate psoriasis appearance
multiple small, tear dropped shaped, erythematous plaques on the trunk
cause of Guttate psoriasis
streptococcal infection in young adults
treatment of Guttate psoriasis
reassurance and a topical emollient
first line treatment in psoriasis
potent topical corticosteroid and topical vitamin D preparations
nail changes associated with psoriasis
nail pitting
Onycholysis
Subungual hyperkeratosis (thickening of nail bed)
“oil-drop” lesions
side effects of ciclosporin (5 Hs)
hypertrophy of the gums
hypertrichosis
hypertension
hyperkalaemia
hyperglycaemia (diabetes)
most common lichenoid disorder
lichen planus
what are lichenoid disorders
conditions characterised by damage to basal epidermis
recognised triggers of lichen planus
hep c infection
allergic contact dermatitis
localised skin injury/infection
medications
nail involvement in lichen planus
longitudinal ridging
where do cutaneous lichen planus lesions typically appear
flexor aspects of the wrist and ankles
what is acne vulgaris
common chronic disorder of the pilo-sebaceous unit, resulting in blockage of the follicle, formation of comedones and inflammation
appearance of lichen planus (5 Ps)
purple
pruritic
papular
polygonal
planar (flat topped)
what are comodones
blackheads/whiteheads- buildup of keratin and sebum
what is acne rosacea
common skin condition characterised by facial flushing that may be triggered by a number of factors
who does acne rosacea most commonly affect
middle aged women, particularly those with a fair complexion
rosacea triggers
sunlight
alcohol
spicy foods
stress
what is Rhinophymatous rosacea
subtype of rosacea more common in men- swollen, bulbous nose with enlarged sebaceous glands and prominent hair follicles
first line treatment for papulopustular rosacea
topical ivermectin once daily for 8–12 weeks
alternatives to topical ivermectin for papulopustular rosacea
topical metronidazole or topical azelaic acid applied twice daily
first line treatment for rosacea
topical brimonidine 0.5% gel once daily on an ‘as needed’ basis, for temporary relief of symptoms
medical treatment of eczema
- emollients
- topical steroids
- phototherapy- UVB
- systemic immunosuppressants
- biologic agents
which gene is affected in atopic dermatitis
filaggrin gene
what is discoid eczema
eczema in circle/oval patches
other types of eczema which are often atopic too
discoid eczema
photosensitive eczema
common term used to describe a mild, non-inflamed form of seborrheic dermatitis
dandruff
what is Auspitz’ sign
removing scale reveals pin-point bleeding (psoriasis)
what is keobener phenomenon
psoriasis may develop in sites of trauma- 2-6 weeks after trauma sustained
- catches, burns (+sunburn), other dermatoses, surgical trauma
what is a flexural rash
a skin rash that appears in the creases of the body, such as the elbows and knees
what is herpes labialis
a cold sore
moderate acne treatment
topical treatment and oral antibiotics/dianette
severe acne treatment
isotretinoin (roaccutane)
what is pityriasis rosea
a self limiting rash that resolves after 10 weeks characterised by a herald patch and fir-tree pattern eruption
pityriasis rosea triggers
viruses- covid 19, flu etc
drugs- gold, ACEi, penicillamine, biologics
vaccines- hep b, pneumococca
what is a ‘herald patch’
red-pink oval/discoid plaque with scale on trunk/upper arm/thigh
which drug used to treat acne should be avoided during pregnancy
topical isotretinoin (roaccutane)
which topical antibiotics used to treat acne should be avoided when breastfeeding
tetracyclines eg doxycycline, tetracycline
what are open comedones
blackheads
what are closed comedones
whiteheads
examples of drugs that may tigger psoriasis
beta blockers
lithium
anti-malarial drugs
parakeratosis is seen in histology of psoriasis, what is parakeratosis?
presence of nuclei in keratin layer
how long does it take for skin cells to be replaced in a normal individual compared to someone with psoriasis?
normal- 3-4 weeks
psoriasis- 3-7 days
what is seen in the histology of psoriasis
acanthosis- thickened epidermis
parakeratosis- presence of nuclei in keratin layer
what are Wickham’s striae
white lacy lines on the surface- seen in lichen planus
what are features of oral lichen planus
ulceration
wickhams striae
burning sensation on eating
histological features of lichen planus
irregular sawtooth acanthosis
hypergranulosis
orthohyperkeratosis
cytoid bodies
what is orthohyperkeratosis
thickening of the keratin layer characterized by an increase in keratinocytes that are fully differentiated- do not retain nuclei
what is tinea
tinea is a superficial fungal infection of the skin caused by dermatophytes, a group of fungi that invade and grow in dead keratin, commonly referred to as ‘ringworm’
what is tinea commonly known as
ringworm
what is tinea pedis
athletes foot
what investigation should be carried out before and after treatment of oral antifungals
liver function tests- oral antifungals can cause jaundice, cholestasis, and hepatitis
what is molluscum contagiosum
common, contagious skin infection caused by the molluscum contagiosum virus, a member if the poxvirus family
how is molluscum spread
direct skin-to-skin contact
who does molluscum most often occur in
children and people who are immunocompromised
which children are more susceptible to molluscum
children with eczema
where is molluscum most commonly found in adults
genitals- from STI
what family is the molluscum contagiosum virus apart of
poxvirus family
how long does molluscum usually take to resolve
within 18 months
what is acanthosis nigricans
a skin condition characterised by a velvety papillomatous overgrowth of the epidermis
causes of acanthosis nigricans
T2DM
GI cancer
obesity
polycystic ovarian syndrome
acromegaly
cushings syndrome
hypothyroidism
familial
Prader-Willi syndrome
drugs- COCP
what is folliculitis
Folliculitis refers to the inflammation of a hair follicle that results in the formation of papules or pustules, commonly known as ‘pimples’
most common bacterial infection causing folliculitis
staph aureus
particular form of folliculitis often seen in HIV patients
eosinophilic folliculitis
what is urticaria
urticaria describes a local or general superficial swelling of the skin
most common cause of urticaria
allergy
what is urticaria aka
hives
first line treatment of urticaria (hives)
non-sedating antihistamines (eg loratadine, cetirizine)
4 most common drugs known for precipitating to urticaria
NSAIDs
aspirin
penicillin
opioids
what antibiotics used to treat acne are safe during pregnancy/breastfeeding
trimethoprim
erythromycin
what antibiotics are used to treat acne for patients under 12 years old
clarithromycin
erythromycin
where is the location of tinea barbae
beard
where is the location of tinea capitis
head (cap)
where is the location of tinea corporis
body (corp)
where is the location of tinea manuum
hand
where is the location of tinea unguium
nail
where is the location of tinea cruris
groin
