Dermatology Flashcards
What is ecthyma?
Secondary infection of eczema with staphylococcus aureus
Causes deeper ulcers with thick yellow/grey scabs
What causes bullous pemphigoid?
auto-antibodies against antigens between the dermis and epidermis
What conditions are pyoderma gangrenosum associated with?
Rheumatological conditions e.g. RA, Ulcerative colitis
How does pyoderma gangrenosum present?
Painful rash on lower leg
Purplish, indurated edges
Often start as erythema nodosum or a small pustule which rapidly deepens and widens
Which type of skin cancer causes only local invasion rather than distant metastasis?
Basal cell carcinoma
What is erythroderma?
DERM EMERGENCY
Redness >90% of the whole body Caused by: Drugs (NSAIDs, antibiotics, anticonvulsants, antimalarials) Eczema Psoriasis Pityriasis rubra pilaris
What are the main concerns in erythroderma?
Dehydration and hypotension- loss of fluid autoregulation
Infection- loss of protective barrier
Hypothermia- loss of thermoregulation
What are the management options for vitiligo?
Steroids
Phototherapy
What is eczema herpeticum?
Herpes simplex complication of eczema
Causes extensive crusted papules, punched-out blisters and erosions
Rash is painful and associated with fever and malaise
Derm emergency, especially if over eyelid- risk of blindness
How is eczema herpeticum managed?
Oral aciclovir 400–800 mg 5 times daily, or, if available, valaciclovir 1 g twice daily, for 10–14 days or until lesions heal. - same day dermatological review
Intravenous aciclovir is prescribed if the patient is too sick to take tablets, or if the infection is deteriorating despite treatment. If eye involvement, go straight to IV treatment.
What nail changes are associated with psoriasis?
Nail pitting Leukonychia Onycholysis Subungal hyperkeratosis Subungal haemorrhage
= collectively known as psoriatic onychodystrophy
Where does scabies commonly affect?
Between the fingers
Genitalia
Permethrin treatment
What conditions are erythema nodosum associated with?
IBD TB Strep throat infections Sarcoid Drugs
What bacterial superinfection causes a green hue to lesions?
Pseudomonas
Where are the most common sites to suffer eczema?
In children: face and extensor surfaces
In adults: flexor surfaces
What are potential complications of eczema?
Bacterial superinfection e.g. staph aureus and impetiginastion
Viral superinfection e.g. eczema herpeticum
Other atopic conditions
Interruption to quality of life
Which drugs commonly cause photosensitivity?
Tetracyclines: doxycycline, limecycline Ciprofloxacin Amiodarone Hydroxychloroquine Isotretinoin
How is eczema classically managed?
- Emollient treatment, non-bio washing detergens, avoiding perfumes and allergens
- Topical steroids
- Immunomodulators: topical tacrolimus
Addition of bandage occlusion and wraps - Phototherapy: 2-3x weekly sessions 6-8w
- Systemic immunosuppression
What counselling points are there for emollient use?
- Apply as regularly as possible
- Apply 30mins BEFORE steroids
- Apply in direction of hair growth
- Stay away from flames + be aware of clothing being flammable
- Be aware of slipping in the bath
What counselling points are there for steroid use?
- Only use as often as prescribed
- Only apply to affected areas and very thin layer
- Apply 30 mins after emollients
- 1 finger tip unit = Two palm sized areas
- Don’t use on areas of infection
- Wash hands after use
What is the steroid ladder?
- Hydrocortisone 0.1-2.5% (1% usually good place to start)
- Eumovate
- Betnovate
- Dermovate
How is bacterial superinfection of eczema usually treated?
Topical antimicrobials: fusidic acid, neomycin
Systemic antibiotics: flucloxacillin first line (or erythromycin if allergic)
What are potential complications of eczema herpeticum?
Blindness Herpes hepatitis Encephalitis Pneumonitis DIC death
What is the classic presentation of psoriasis?
Itchy, scaly, erythematous plaques on the extensor surfaces
Nail changes
Plaques may develop on scars/areas of minor trauma
May have family history
Improvement in sunlight
May have associated arthropathy
What is guttate psoriasis?
Small, red, teardrop-shaped lesions on the trunk and limbs
Common occurs following strep throat infection
Self-limiting and disappear within 3 months- no treatment required