Dermatology 2 Flashcards
What is pre tibial myxoedema?
Pretibial myxoedema
symmetrical, erythematous lesions seen in Graves’ disease
shiny, orange peel skin
Different shin lesions?
Erythema nodosum
symmetrical, erythematous, tender, nodules which heal without scarring
most common causes are streptococcal infections, sarcoidosis, inflammatory bowel disease and drugs (penicillins, sulphonamides, oral contraceptive pill)
Pretibial myxoedema
symmetrical, erythematous lesions seen in Graves’ disease
shiny, orange peel skin
Pyoderma gangrenosum
initially small red papule
later deep, red, necrotic ulcers with a violaceous border
idiopathic in 50%, may also be seen in inflammatory bowel disease, connective tissue disorders and myeloproliferative disorders
Necrobiosis lipoidica diabeticorum
shiny, painless areas of yellow/red skin typically on the shin of diabetics
often associated with telangiectasia
what inheritance pattern is hereditary hemorrhagic telangiectasia?
autosomal dominant pattern of inheritance and age-related penetrance
what is hereditary haemorrhage telangiectasia?
Also known as Osler-Weber-Rendu syndrome, hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant condition characterised by (as the name suggests) multiple telangiectasia over the skin and mucous membranes. Twenty percent of cases occur spontaneously without prior family history.
Diagnostic features of hereditary haemorrhage telangiectasia?
There are 4 main diagnostic criteria. If the patient has 2 then they are said to have a possible diagnosis of HHT. If they meet 3 or more of the criteria they are said to have a definite diagnosis of HHT:
epistaxis : spontaneous, recurrent nosebleeds
telangiectases: multiple at characteristic sites (lips, oral cavity, fingers, nose)
visceral lesions: for example gastrointestinal telangiectasia (with or without bleeding), pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM
family history: a first-degree relative with HHT
what is pellagra?
Pellagra is a caused by nicotinic acid (niacin, B3) deficiency. The classical features are the 3 D’s - dermatitis, diarrhoea and dementia.
Pellagra may occur as a consequence of isoniazid therapy (isoniazid inhibits the conversion of tryptophan to niacin) and it is more common in alcoholics.
Features of Pellagra?
dermatitis (brown scaly rash on sun-exposed sites - termed Casal’s necklace if around neck)
diarrhoea
dementia, depression
death if not treated
Lichen plants vs lichen sclerosus?
planus: purple, pruritic, papular, polygonal rash on flexor surfaces. Wickham’s striae over surface. Oral involvement common
sclerosus: itchy white spots typically seen on the vulva of elderly women
treatment of lichen planus?
potent topical steroids are the mainstay of treatment
benzydamine mouthwash or spray is recommended for oral lichen planus
extensive lichen planus may require oral steroids or immunosuppression
What is bullous pemphigoid?
Bullous pemphigoid is an autoimmune condition causing sub-epidermal blistering of the skin. This is secondary to the development of antibodies against hemidesmosomal proteins BP180 and BP230.
Features of Bullous pemphigoid?
itchy, tense blisters typically around flexures
the blisters usually heal without scarring
there is stereotypically no mucosal involvement (i.e. the mouth is spared)
in reality around 10-50% of patients have a degree of mucosal involvement. It would, however, be unusual for an exam question to mention mucosal involvement as it is seen as a classic differentiating feature between pemphigoid and pemphigus.
What will a skin biopsy in Bullous pemphigoid show?
immunofluorescence shows IgG and C3 at the dermoepidermal junction
what is necrobiosis lipoidica diabeticorum?
Necrobiosis lipoidica diabeticorum. This condition is a rare skin disorder of unclear aetiology, often associated with diabetes mellitus. It typically presents as shiny, atrophic, yellow-brown plaques on the shins with telangiectasia and occasional ulceration. The patient’s age, the location of the lesion and its description fit this diagnosis.
Management of Bullous phemphigoid?
referral to a dermatologist for biopsy and confirmation of diagnosis
oral corticosteroids are the mainstay of treatment
topical corticosteroids, immunosuppressants and antibiotics are also used
treatment for rosacea with predominant erythema/flushing?
topical brimonidine gel may be considered for patients with predominant flushing but limited telangiectasia
brimonidine is a topical alpha-adrenergic agonist
this can be used on an ‘as required basis’ to temporarily reduce redness
it typically reduces redness within 30 minutes, reaching peak action at 3-6 hours, after which the redness returns to the baseline
treatment for rosacea with papules/pustules?
mild-to-moderate papules and/or pustules
topical ivermectin is first-line
alternatives include: topical metronidazole or topical azelaic acid
moderate-to-severe papules and/or pustules
combination of topical ivermectin + oral doxycycline
treatment of acne in pregnancy?
use oral erythromycin if treatment needed
Pregnant lady develops rash - when should steroids be used?
Presence of blisters
Pemphigoid gestationis is a blistering rash which develops around the umbilicus before spreading to other areas and, in many cases will be treated with oral steroids. Atopic eruption and polymorphic eruption of pregnancy are non-blistering rashes which would only be treated with oral steroids if symptoms are severe or if topical treatments had failed. Blistering is specific to pemphigoid gestationis which can have complications such as secondary infection and premature delivery.
what conditions are associated with seborrhoea dermatitis?
HIV
Parkinson’s disease
Features of seborrhoeic dermatitis?
eczematous lesions on the sebum-rich areas: scalp (may cause dandruff), periorbital, auricular and nasolabial folds
otitis externa and blepharitis may develop
management of scalp seborrhoeic dermatitis?
the first-line treatment is ketoconazole 2% shampoo
over the counter preparations containing zinc pyrithione (‘Head & Shoulders’) and tar (‘Neutrogena T/Gel’) may be used if ketoconazole is not appropriate or acceptable to the person
selenium sulphide and topical corticosteroid may also be useful
Management of face and body seborrhoeic dermatitis?
topical antifungals: e.g. ketoconazole
topical steroids: best used for short periods
difficult to treat - recurrences are common
Features of zinc deficiency?
Features
acrodermatitis: red, crusted lesions
acral distribution
peri-orificial
perianal
alopecia
short stature
hypogonadism
hepatosplenomegaly
geophagia (ingesting clay/soil)
cognitive impairment
What is acrodermatitis enteropathica?
Acrodermatitis enteropathica is a recessively inherited partial defect in intestinal zinc absorption.
what does Dermatitis in acral, peri-orificial and perianal distribution suggest?
zinc deficiency
what is pityriasis versicolor cased by?
what are the features?
what is the management ?
caused by a superficial cutaneous fungal infection caused by Malassezia furfur
Features
most commonly affects trunk
patches may be hypopigmented, pink or brown (hence versicolor). May be more noticeable following a suntan
scale is common
mild pruritus
Management
topical antifungal. NICE advises ketoconazole shampoo as this is more cost effective for large areas
if failure to respond to topical treatment then consider alternative diagnoses (e.g. send scrapings to confirm the diagnosis) + oral itraconazole
what is Pompholyx?
what are the features?
How is it. managed?
Pompholyx is a type of eczema which affects both the hands (cheiropompholyx) and the feet (pedopompholyx). It is also known as dyshidrotic eczema.
Pompholyx eczema may be precipitated by humidity (e.g. sweating) and high temperatures.
Features
small blisters on the palms and soles
pruritic
often intensely itchy
sometimes burning sensation
once blisters burst skin may become dry and crack
Management
cool compresses
emollients
topical steroids
causes of erythroderma?
eczema
psoriasis
drugs e.g. gold
lymphomas, leukaemias
idiopathic
what is Tinea and what are the different types?
Tinea is a term given to dermatophyte fungal infections. Three main types of infection are described depending on what part of the body is infected
tinea capitis - scalp
tinea corporis - trunk, legs or arms
tinea pedis - feet
What is Tinea capitis commonly known as?
Scalp ringworm
In which population is Tinea capitis mainly seen?
Children
What serious condition can form if Tinea capitis is untreated?
Kerion
a raised, pustular, spongy/boggy mass
What is the most common cause of Tinea capitis in the UK and the USA?
Trichophyton tonsurans
may also be caused by Microsporum canis acquired from cats or dog
What diagnostic method shows green fluorescence for lesions caused by Microsporum canis?
Wood’s lamp
What is the most useful investigation for diagnosing Tinea capitis?
Scalp scrapings
According to NICE guidelines, what is the oral antifungal treatment for Trichophyton tonsurans infections?
Terbinafine
Which oral antifungal is recommended for Microsporum infections?
Griseofulvin
What topical treatment should be given for the first two weeks to reduce transmission of Tinea capitis?
Ketoconazole shampoo
what causes tinea corporis?
ringworm
causes include Trichophyton rubrum and Trichophyton verrucosum (e.g. From contact with cattle)
what is the management of ringworm?
oral fluconazole
what is Tinea pedis?
Tinea pedis (athlete’s foot)
characterised by itchy, peeling skin between the toes
common in adolescence
What factors may exacerbate psoriasis?
trauma
alcohol
drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
withdrawal of systemic steroids
Streptococcal infection may trigger guttate psoriasis.
Causes of pyoderma gangrenosum?
idiopathic in 50%
inflammatory bowel disease in 10-15%
ulcerative colitis
Crohn’s
rheumatological
rheumatoid arthritis
SLE
haematological
myeloproliferative disorders
lymphoma
myeloid leukaemias
monoclonal gammopathy (IgA)
granulomatosis with polyangiitis
primary biliary cirrhosis
what is pyoderma gangrenosum classified as?
pyoderma gangrenosum is classified as a neutrophilic dermatosis
neutrophilic dermatoses are skin conditions characterised by dense infiltration of neutrophils in the affected tissue and this is often seen on biopsy
Features of pyoderma gangrenosum?
typically on the lower limb
often at sit of minor injury
usually starts quite suddenly - as a small pustule red bump or blood blister
later features - this skin breaks down rsulting in an ulcer - often painful
The edge of the ulcer is ofted described as purple violaceous and undermined
the ulcer itself is deep and necrotic
fever and myalgia
Management of pyoderma?
oral steroids first line
other immunosuppressive therapy, for example, ciclosporin and infliximab, have a role in difficult cases
what is hyperhidrosis?
Hyperhidrosis describes the excessive production of sweat.
what is the management of hyperhidrosis?
topical aluminium chloride preparations are first-line. Main side effect is skin irritation
iontophoresis: particularly useful for patients with palmar, plantar and axillary hyperhidrosis
botulinum toxin: currently licensed for axillary symptoms
surgery: e.g. Endoscopic transthoracic sympathectomy. Patients should be made aware of the risk of compensatory sweating
what causes porphyria cutanea tarda?
Porphyria cutanea tarda is the most common hepatic porphyria. It is due to an inherited defect in uroporphyrinogen decarboxylase or caused by hepatocyte damage e.g. alcohol, hepatitis C, oestrogen.
Features of Porphyria cutanea tarda?
classically presents with photosensitive rash with blistering and skin fragility on the face and dorsal aspect of hands (most common feature)
hypertrichosis
hyperpigmentation
Investigations for Porphyria cutanea tarda?
urine: elevated uroporphyrinogen and pink fluorescence of urine under Wood’s lamp
serum iron ferritin level is used to guide therapy
Management of Porphyria cutanea tarda?
chloroquine
venesection
preferred if iron ferritin is above 600 ng/ml
what is Bullous pemphigoid?
Bullous pemphigoid is an autoimmune condition causing sub-epidermal blistering of the skin.
what antibodies are seen in Bullous pemphigoid?
antibodies against hemidesmosomal proteins BP180 and BP230.
How does Bullous Pemphigoid present?
More common in elderly patients
itchy, tense blisters typically around flexures
the blisters usually heal without scarring
there is stereotypically no mucosal involvement (i.e. the mouth is spared)
in reality around 10-50% of patients have a degree of mucosal involvement. It would, however, be unusual for an exam question to mention mucosal involvement as it is seen as a classic differentiating feature between pemphigoid and pemphigus.
what does a skin biopsy show in bullous pemphigoid?
immunofluorescence shows IgG and C3 at the dermoepidermal junction
Management of Bullous pemphigoid?
referral to a dermatologist for biopsy and confirmation of diagnosis
oral corticosteroids are the mainstay of treatment
topical corticosteroids, immunosuppressants and antibiotics are also used
How to manage fungal nail infecition?
no treatment if asymptomatic
f limited involvement (≤50% nail affected, ≤ 2 nails affected, more superficial white onychomycosis): topical treatment with amorolfine 5% nail lacquer; 6 months for fingernails and 9 - 12 months for toenails
if more extensive involvement due to a dermatophyte infection: oral terbinafine is currently recommended first-line; 6 weeks - 3 months therapy is needed for fingernail infections whilst toenails should be treated for 3 - 6 months
if more extensive involvement due to a Candida infection: oral itraconazole is recommended first-line; ‘pulsed’ weekly therapy is recommended
Management of facial Hirsutism in PCOS patients?
facial hirsutism: topical eflornithine - contraindicated in pregnancy and breast-feeding
What is systemic mastocytosis associated with?
Increased histamine production and increased gastric acid secretion
This predisposes patients to gastritis and peptic ulcers.
What predisposes patients with systemic mastocytosis to gastritis and peptic ulcers?
Increased histamine production and increased gastric acid secretion.
What is urticaria pigmentosa?
A rash characterised by innumerable reddish-brown papules that undergo an urticarial reaction on irritation.
This reaction upon irritation is known as Darier’s sign.
What is Darier’s sign?
The urticarial reaction that occurs upon irritation of urticaria pigmentosa.
In which age group is urticaria pigmentosa typically seen?
Childhood forms of the disease.
Can urticaria pigmentosa occur in adults?
Yes, it can also occur in adults and tends to persist for longer.
What laboratory findings are associated with systemic mastocytosis?
Raised serum tryptase and urinary histamine levels.
