Dermatology Flashcards
Define vernix caseosa
Chalky-whit greasy coat of newborn infants
Skin in preterm infants
Thin Poorly keratonised Transepidermal water loss Lacking subcutaeous fat Unable to sweat
Features bullous impetigo
Uncommon
Blitering form of impetigo
Causes by staphylococcus aureus
Mx Bullous Impetigo
Systemic antibiotics .e.g. flucloxacillin
Features congenital pimented naveai
Rare
Involve extensive areas of skin (>9cm in diameter)
4-6% risk of malignant melanoma
Features albinism
Defective biosynthesis of melanin Lack of pigmentation of skin and eye Failure to develop fixation reflex Pendular nystagmus Photophobia (constant frowning)
Mx albinism
Correction of refractive errors
Fitting of tinted lenses
Sun protection
Features epidermolysis Bullosa
Blistering of the skin and mucous membranes
Blisters occur spontaneously and following minor tauma
Oral ulceration
Mx epidermolysis bullosa
Avoidance of minor trauma
Maintenance of adequate nutrition
Analgesia when dressings changed
Cx epidermolysis bullosa
fusion of fingers and toes
Limb contractures from repeated blistering and healing
Features collodion baby
Dry and scaly skin
Infants born with taut, shiny, parchment like membrane
Risk of dehydration
Mx Collodion baby
Application of emmoliants
Membrane fissues and separates within a few weeks
Causes of nappy rash
Irritant contact dermatitis Infantile seborroeic dermatitis Candida infection Atopic eczema Acrodermatitis enteropathica Langerhans cell histiocytosis Wiskott-Aldrich syndrome
Features irritant dermatitis nappy rash
Occurs if nappies changed infrequently or in diarrhoea
Irritant affect of urine on the skin
Urea splitting organisms in faeces increase alkalinity
Affects converse surfaces of buttocks, perineal, lower abdo, top of thighs
Sparing of flexures
Erythmatous with scalded appearance
Erosions and ulcer formation present
Features candida nappy rash
Erythematous
Includes skin flexures
Satellite lesions
Mx candida nappy rash
Topical antifungal
Mx irritant dermatitis nappy rash
Mild topical corticosteroid
Features Infantile seborrhooeic dermatitis
Present within 3m
Scalp
Erythematous scaly eruption
Scales form a thick yellow adherent layer (cradle cap)
Spread to face, behind ears, flexures and napkin area
Not itchy- child unbothered
Mx Infantile seborrhoeic dermatitis
Emollients
Scales cleared with sulfur and salicylic acid ointment
-applied daily for a few hours and washed off
Mild topical corticosteroid- widespread body eruptions
+/- antibacterial and antifungal
Features atopic eczema
Genetic deficiency in the skin barrier Onset within 1y Uncommon in first 2m Associated with atopy (1/3 develop asthma) Exclusive breastfeeding can delay onset Usually self resolves
Clinical Diagnosis atopic eczema
Itchy rash
Scratching
Excoriated areas become weepy, erythematous and crusted
Dry skin
Linchification from prolonged scratching and rubbing
dDx Itchy rash
Atopic eczema Chickenpox Urticaria/allergy contact dermatitis Insect bite Scabies Fungal infection Pityriasis rosea
Causes of exacerbation of eczema
Bacterial infection.e.g. strep, staph Viral infection .e.g. herpes Ingestion of allergen .e.g. Egg Contact with irritant or allergen Environment .e.g. heat, humidity Change or reduction in medication Psychological stress Unexplained
Distribution of atopic eczema
Infant >2m: predominantly face, also trunk
Older children: flexor and friction surfaces
Complications atopic eczema
Infection .e.g. staphylococcus, streptococcus
Eczema herpaticum
Regional lymphadenopathy
Mx eczema
Avoidance of precipitants -allergens .e.g. cows milk -avoiding nylon and woollen garments -cutting nails and using mittens Emollients Topical corticosteroids Immunomodulators (children >2y): topical tacrolimus ointment or pimecrolimus cream Occlusive bandages: impregnanted with zinc/tar paste -worn overnight for 2-3d at a time Wet stockinette wraps in widespread itching -diluted topical steroids with emollient Antibiotics/antiviral/antifungal Dietary elimination Psychological support
Features viral warts
Caused by human papilomavirus
Common in children
Usuaully on fingers and soles (verrucae)
Most disappear spontaneously over a few months
Mx viral warts
Only indicated for cosmesis and painful lesions
Daily application of proprietary salicylic acid and lactic acid paint / glutaraldehyde lotion
Cryotherapy with liquid nitrogen- only older children
Features molluscum contagiosum
Caused by poxvirus
Small, skin coloured, pearly papules with central umbilication
Often widespread
Spontaneously regress within a year
Mx molluscum contagiosum
Topical antibacterial to prevent 2’ infection
Cryotherapy for chronic lesions in older children
Features ringworm
Dermatophyte fungi invasion f keratinous structures
Annual ring appearance of skin lesions
Kerions: severe inflammatory pustular ringworm
Tinea capitis: scalp, acquired from pets, scaling and patchy alopecia
Ix Tinea capitis
Examination under filtered UV woods light shows bright greenish yellow flourescence of infected hairs
Microscopic examination of skin scrapings show fungal hyphae
Definitive identification of fungi is by culture
Mx ringworm
Topical antifungal preparation
Systemic antifungal in severe infection and scalp
Treatment of household animals if infected
Features Scabies
Infestion by burrowing along stratum corneum
Severe itching occurs 2-6w after infestation
Worse in warm conditions and at night
Scabies locations
Older children: -between fingers and toes -axillae -flexor aspect of wrists -belt line -nipples,penis, and buttocks Infants: -palms and soles -trunk Babies: -head, face and neck involvement (uncommon)
Cx Scabies
Excoriation of skin causing eczematous/urticarial reaction
2’ bacterial infection
Norweigan scabies
Mx Scabies
Treatment of child and household
Primethaprin cream (5%)- applied to all areas and washed off after 8-12h
-In babies face and scalp should be included
Benzyl benzoate emulsion (25%)- applied below neck only, left for 12h
-smells and has irritant action
Malathion lotoin (0.5%)- applied below neck, left 12h
Features Pediculosis (Headlice)
Typically primary school age
Itching of scalp or nape
Identification of live lice on scalp or nits (egg cases) on hair
Suboccipital lymphadenopathy
Mx Head lice
Dimeticon 4% lotion / Malathion 0.5% aqeous solution
-rubbed onto hair and scalp and left overnight
-repeated 1w later
Wetcombing with fine tooth comb to remove lice
-repeated every 3-4 days for 2 weeks
No school exclusion necessary
Features psoriasis
Familial disorder
Presents after 2y
Plaques and annular lesions
Fine pitting of nails in chronic disease
Features guttate psoriasis
Common in children
Small, raindrop like, oral or round erythematous scaly patches
Trunk and upper limbs
Attack resolves over 3-4m
Mx guttate psoriasis
Bland ointments
Mx Chronic Psoriasis
Coal tar preparations
Calcipotriol (vit D analogue) children>6y
Dithranol preparation in resistant plaque psoriasis
Features Pityriasis Rosea
Acute benign self limiting condition
Single round or oval scaly macule (herald patch)
- 2-5cm in diameter
Trunk, upper arm, neck, or thigh
Numerous smaller dull pink macules develop
Rash follows line of ribs posteriorly (fir tree pattern)
Lesions may be itchy
Resolves within 4-6w
Features Alopecia Areata
Common form of hair loss in children
Hairless non-inflammed smooth areas of skin, usually over scalp
Remnant of broken hairs (exclamation marks) on edge of active patches
Prognosis Alopecia Areata
Usually hair growth occurs within 6-12m in localised hair loss
Poorer prognosis is associated with greater hair loss
Prognosis more guarded in children with atopic disorders
Features Granuloma Annulare
Ringed lesions Flesh coloured non scaling edge Over bony prominences especially hands and feet Usually 1-3cm in diameter Disappear spontaneously within 12m
Features Acnes Vulgaris
Begins 1-2y before onset of puberty
-androgenic stimulation of sebaceous glands
Open and closed comedones, papules, pustules, nodules and cysts
Face, back, chest and shoulders
Cystic and nodular lesions may cause scarring
Exacerbation with menstruation and stress
Mx Acne Vulgaris
Topic treatments: -benzoyl peroxide (keratolytic agent) 1/2 daily -sunshine in moderation -topical antibiotics -topical retinoids Systemic therapy -Oral antibiotics (tetracycline/erythromycin) >12y -Oral retinoid (isotretinoin)
Causes of erythema nodosum
Streptococcal infection Primary TB Inflammatory bowel disease Drug reaction Idiopathic
Causes of erythema multiforme
Herpes simplex Mycoplasma pneumoniae Infections Drug reaction Idiopathic
Features erythema multiforme
Target lesion
Central papule surrounded by erythematous ring
Vesicular or bullous lesions
Features Steven-Johnson Syndrome
Severe bullous form of erythema multiforme
Involvement of mucous membranes
Starts with URTI
Eye involvement: conjunctivitis, corneal ulceration, uveitis
Features Urticaria
Flesh coloured wheals Delayed hypersensitivity reaction Commonly on legs Bite from flea, bedbug, animal/bird mite Irritation Vesicles Papules Wheals Secondary infection due to scratching common
Features hereditary angioedema
Rare AD Deficiency or dysfunction of C1-esterase inhibitor Subcutaneous swelling Abdominal pain Physical trauma or stress as a trigger Lasts a few hours Can cause respiratory obstruction
Mx hereditary angiodema
Resolves over few days
Severe acute attack: purified preparation of inhibitor
