Derm Flashcards
A 7-month-old boy is brought to the emergency department by his family. He has a history of eczema, which is usually well-controlled, and previous chickenpox. Over the last 5 days, he has developed a worsening rash. This started with clusters of blisters on the face and neck. These have now spread to the trunk and arms.
You find a symmetrical monomorphic eruption of small blisters with central umbilication. They are filled with yellow fluid and blood-stained. The skin surrounding these clusters is normal. The patient is febrile and lethargic.
What is the most likely causative organism?
herpes simplex virus
the boy has eczema herpeticum
Common features of eczema herpeticum
- symmetrical
- clusters of blisters
- fever
- malaise
- central umbilication
How would the following infections present in children:
- staph aureus:
- strep pyogenes:
- trichophyton rubrun:
- VZV:
- staph aureus: staphylococcal scalded skin syndrome, wrinkled skin, large, fluid-filled blisters, generalised exfoliatibe dermaitits
- strep pyogenes: impetigo
- trichophyton rubrun: tinea corporis, single circular patch with erythema and scaling, would not be too widespread
- VZV: chickenpox/shingles
tx for children with eczema herpetricum
IV aciclovir
tx for children with new onset purpura
referred immediately for investigations to exclude ALL and meningococcal disease
petechiae vs purpura - which is a common finding in children
petechiae can be seen in a viral illness or with increased superior vena cava pressure (e.g. following a cough)
purpura are never a normal finding in children
which drugs can cause purpura in adults?
quinine, antiepileptics, antithrombotics
_____ in a contraindication to topical AND oral retinoid tx
pregnancy
tetracyclines should be avoided in____________
pregnant or breastfeeding women and in children younger than 12 years of age
for acne, __________________________ should always be co-prescribed with oral antibiotics to reduce the risk of antibiotic resistance developing
a topical retinoid (if not contraindicated) or benzoyl peroxide
for acne, gram-negative folliculitis can develop if you use long term abx. Treat with ______
high-dose trimethoprim
A 16-year-old girl presents to the GP with swollen lips and a tingling sensation in her mouth, accompanied by small red raised spots around her mouth. She reports that these symptoms began approximately two hours after consuming shrimp. She has no known allergies and has not previously experienced similar symptoms. The patient denies experiencing any difficulty breathing or swallowing.
What does she have? Whats the frst line tx?
urticaria ( swelling and wheals confined to the oral region following an allergic reaction)
course of oral loratidine/cetirizine (non-sedating, unlike say chlorpheniramine)
tx for severe/resistant ultricaria
prednisolone alongside antihistamines
A 30-year-old female in her third trimester of pregnancy mentions during an antenatal appointment that she has noticed an itchy rash around her umbilicus. This is her second pregnancy and she had no similar problems in her first pregnancy. Examination reveals blistering lesions in the peri-umbilical region and on her arms. What is the likely diagnosis?
Pemphigoid gestationis - pruritic blistering lesions, develop in peri-umbilical regions, spread to trunk, back, buttocks and arms.
- 2nd/3rd trimester
- tx with oral corticosteroids
A 54-year-old woman presents to her general practitioner with a rash affecting her cheeks, nose, and forehead. The rash is worse when exposed to the sun. She has no past medical history.
On examination, there is an erythematous rash affecting her nose, cheeks, and forehead diffusely and involving the nasolabial folds. There is a minimal amount of papules and pustules visible.
what is the Dx?
Rosacea
Tx for rosacea
mild/moderate: topical ivermectin
severe/resistant: combination of topical ivermectin + oral doxycycline
name of phenomenon new leseions develop on previously unaffected skin after trauma/chemial irritation
koebner phenomenon
A 56-year-old gentleman presents to the dermatology clinic. Over the last few weeks, he has noticed a new, enlarging lesion on his cheek which sometimes bleeds. On examination, he has Fitzpatrick skin type I, multiple melanocytic naevi over his body, and the lesion in question is a large, black, dome-shaped lump, of 1cm diameter, located on his right cheek. What is this lesion most likely to represent?
Nodular melanoma: Red or black lump, oozes or bleeds, sun-exposed skin
- tx with amoxicllin
- widepsread erythematous bullae and vesicles
- lesions in oral muscoa and eyes
- Nikolskys sign positive
What is the Dx?
topical epidermal necrolysis
nectrotising fasciitis often starts as _____
localised cellulitis that then spreads
skin overlying infection can appear tinged grey
drugs known to produce TEN
phenytoin
sulphonamides
allopurinol
penicillins
carbamazepine
NSAIDs
SNAPAC
A 10-year-old child is admitted with severe 30% burns following a house fire. After wound cleaning and dressings he is admitted to critical care. 1 day following skin grafts he becomes tachycardic and hypotensive. He vomits twice and this shows evidence of haematemesis
Dx?
Curlings ulcer - stress ulcers that occur in the duodenum of burns patients
Eletcrical high voltage burns are associated with _________. Tx with aggressive IV fluid resuscitation.
rhabodmyolysis
A 45-year-old man is admitted after his clothing caught fire. He suffers a full thickness circumferential burn to his lower thigh. He complains of increasing pain in lower leg and on examination there is parasthesia and severe pain in the lower leg. Foot pulses are normal
Dx?
Compartment syndrome as burns have constricted the limb, perform eshcarotomy
Which condition is associated with each of these pathophysiological processes?
- release of epidermal toxins A and B:
- release of igE from plasma cells:
- formation of igA antibodies:
- latent reactivation of herpes zoster virus:
- release of histamine from mast cells:
- release of epidermal toxins A and B: SSSS
- release of igE from plasma cells: atopic dermatitis
- formation of igA antibodies: dermatitis herpetiformis
- latent reactivation of herpes zoster virus: shingles
- release of histamine from mast cells: urticaria
which drug is known to exacerbate plaque psoriais?
betablockers, NSAIDs, lithium, antimalarials
plaque:
- propanolol (BB)
- lithium
- aspirin (NSAID)/ACEI
- quinine (antimalarial)
- eliminating steroids
On examination, there are multiple clusters of well-demarcated papules, around 0.5cm in diameter, with an umbilicated centre over the trunk and face. The child seems settled and his mother reports no recent change in behaviour.
Dx?
Molluscum contagiosum caused by poxvirus
Scabies tx
In scabies, advise all close contacts to be treated as well as the patient twice, with applications one week apart
2 doses of permethrin cream
Tx for crusted scabies
in those with suppressed immunity, especially HIV
ivermectin
Shingles - paracetamol, ibuprofen, codeine and amitriptyline are all not helping. What do you add for refractory pain?
Corticosteroids (prednisolone)
In people over 50, well-circumscribed plaques or papules with a ‘stuck on’ appearance, and most commonly affect the torso or face. The colour of the lesions can vary, but they are most commonly grey-brown or black. Typically the lesions are asymptomatic.
Dx?
Seborrhoeic keratosis
Combination of thrombocytopenia + prolonged APTT, with background of recurrent DVTs, suggest ________.
Common skin findinging in pts with this condition:
antiphospholipid syndrome
livedo reticularis: purplish, lace-patterened discolouration
