Dermatology Flashcards
causes of acanothis nigricans
- type 2 diabetes mellitus
- gastrointestinal cancer
- obesity
- polycystic ovarian syndrome
- acromegaly
- Cushing’s disease
- hypothyroidism
- Prader-Willi syndrome
- drugs
- combined oral contraceptive pill
- nicotinic acid
what is the common bacterium that causes acne
Propionibacterium acnes
what is the first-line management of acne
a single topical therapy containing a retinoid and benzoyl peroxide
what is the second-line treatment of acne vulgaris
- after trialling a topical treatment containing a retinoid and benzoyl peroxide
- try a combination therapy of a topical antibiotic, topical retinoid and benzoyl peroxide
what is the third line treatment for acne vulgaris
- if topical treatment containing antibiotic, retinoid and benzoyl peroxide doesn’t work then use:
- oral tetracycline such as doxycycline
- if pregnant: erythromycin
- COCP is an alternative
- both oral abx and COCP should be co-prescribed with a topical retinoid
- oral abx should be used for a maximum of months
if oral abx/COCP doesn’t work for acne what treatment should you start
- oral isotretinoin
- should only be prescribed under specialist supervision
- pregnancy is a contraindication so they must be on adequate contraception
what is a contraindication to topical or oral retinoid treatment
pregnancy
try oral erythromycin for months with topical benzoyl peroxide
what is actinic keratoses and what is the management
a common premalignant skin lesion that develops as a consequence of chronic sun exposure
treatment is a 2-3 weeks course of fluorouracil cream - this will cause inflammation that may require hydrocortisone to settle
what do you get at the edges of a lesion of alopecia
small, broken, ‘exclamation mark’ hairs
what is the prognosis of alopecia areata
Hair will regrow in 50% of patients by 1 year, and in 80-90% eventually
what is the treatment of alopecia areata
- since 50% will have their hair grow back in a year and 80% will have it grow back at some point, careful counselling is often all that is needed
- other treatment options include
- topical corticosteroids
- phototherapy
two examples of non-sedating antihistamines
- loratidine
- cetirizine
what is an example of a sedating antihistamine
- chlorpheniramine
apart from drowsiness, what other side effect do sedating antihistamines cause
antimuscarinic properties (e.g. urinary retention, dry mouth)
what is the treatment for athlete’s foot
topical imidazole
what is the most common type of cancer in the western world?
BCC
what are the features of BCC
- sun-exposed sites, especially the head and neck
- pearly, flesh-coloured papule with telangiectasia
- may later ulcerate leaving a central ‘crater’
what type of referral for BCC
routine since metastases are extremely rare
what is bowen’s disease and what is the management
- pre-cancerous skin condition that can lead to SCC
- typically in sun exposed areas on the elderly
- management is topical 5-fluorouracil
- twice daily for 4 weeks
- often results in significant inflammation/erythema. Topical hydrocortisone to control this
what is bullous pemphigoid
autoimmune condition resulting in sub-epidermal blistering
what is the management of bullous pemphigoid
- referral to a dermatologist for biopsy and confirmation of diagnosis
- oral corticosteroids are the mainstay of treatment
how do you assess the extent of a burn
- Wallace’s Rule of Nines: head + neck = 9%, each arm = 9%, each anterior part of leg = 9%, each posterior part of leg = 9%, anterior chest = 9%, posterior chest = 9%, anterior abdomen = 9%, posterior abdomen = 9%
what is dermatitis herpetiformis
autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.
what is a dermatofibroma
it is a common benign skin lesion
like a little bump
often follows skin injury
overlying skin dimples when pinched
what is eczema herpeticum
severe primary infection of the skin by herpes simplex virus 1 or 2
commonly seen in children with atopic eczema and often presents as a rapidly progressing painful rash.
what is the management for exzema herpeticum
potentially life-threatening children should be admitted for IV aciclovir.
what is the fingertip unit
the amount of steroid that is squeezed along the fingertip is enough to treat an area the size of two adult hands with fingers together
what is the fingertip unit
the amount of steroid that is squeezed along the fingertip is enough to treat an area the size of two adult hands with fingers together
name some causes of erythema multiforme
pregnancy
IBD
sarcoidosis
behcet’s
streptococcal infection
TB
what is the main causative organism of fungal nail infections
dermatophytes - mainly Trichophyton rubrum
what is the management of fungal nail infection
oral terbinafine
what is guttate psoriasis
more common in children and adolescents. It may be precipitated by a streptococcal infection 2-4 weeks prior to the lesions appearing
most commonly goes away on its own within 2-3 weeks
what is the most common cause of hirsutism
PCOS
how do you treat hyperhydrosis
topical aluminium chloride preparations
what are the two most common causative organisms in impetigo
Staphylcoccus aureus or Streptococcus pyogenes
what is the first line treatment for impetigo in people who are not systemically unwell or at high risk of complications
hydrogen peroxide 1% cream
how do you treat impetigo if it doesn’t respond to hydrogen peroxide 1% cream or if there is extensive disease
- topical fusidic acid
- Topical mupirocin if MRSA suspected
- if extensive disease or if they are at risk of severe complications
- oral flucloxacillin
- oral erythromycin if penicillin-allergic
what are the school exclusion rules with impetigo
- children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
what is leukoplakia
Leukoplakia is a premalignant condition which presents as white, hard spots on the mucous membranes of the mouth. It is more common in smokers.
Biopsies are usually performed to exclude alternative diagnoses such as squamous cell carcinoma and regular follow-up is required to exclude malignant transformation to squamous cell carcinoma, which occurs in around 1% of patients
what are the features of lichen planus
- lichen planus
- purple
- pruritic
- polygonal
- papular
- most common on the palms, soles, genitalia and flexor surfaces of arms
- if seen in mouth typically a white-lace pattern on the buccal mucosa
how do you treat lichen planus
topical steroids
what are the features of lichen sclerosus
- usually affects genetalia of elderly women
- white patches that may scar
- itch is prominent
- may result in pain during intercourse or urination
- there’s increased risk of vulval cancer