Dermatology Flashcards
1
Q
What is acanthosis nigricans?
A
symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin.
2
Q
What are the causes of acanthosis nigricans?
A
- obesity
- type 2 diabetes mellitus
- polycystic ovary syndrome
- Cushing’s syndrome
- acromegaly
- hypothyroidism
- familial
- Prader-Willi syndrome
- gastrointestinal cancer
- drugs: combined oral contraceptive pill, nicotinic acid
3
Q
What is the pathophysiology of acanthosis nigricans?
A
Insulin resistance → hyperinsulinemia → stimulation of keratinocytes and dermal fibroblast proliferation via interaction with insulin-like growth factor receptor-1 (IGFR1)
4
Q
What are Keratoacanthomas?
A
Benign epithelial tumour.
common with advancing age and rare in young people.
5
Q
What are the features of keratoacanthomas?
A
- look like a volcano or crater
- initially a smooth dome-shaped papule
- rapidly grows to become a crater centrally-filled with keratin
- Spontaneous regression of keratoacanthoma within 3 months is common, often resulting in a scar. Such lesions should however be urgently excised as it is difficult clinically to exclude squamous cell carcinoma. Removal also may prevent scarring.
6
Q
What is the most common malignancy in the lower lip?
A
Squamous cell carcinoma
7
Q
What are the features of squamous cell carcinoma?
A
- typically on sun-exposed sites such as the head and neck or dorsum of the hands and arms
- rapidly expanding painless, ulcerate nodules
- may have a cauliflower-like appearance
- there may be areas of bleeding
8
Q
What are the risk factors for squamous cell carcinoma?
A
- excessive exposure to sunlight / psoralen UVA therapy
- actinic keratoses and Bowen’s disease
- immunosuppression e.g. following renal transplant, HIV
- smoking
- long-standing leg ulcers (Marjolin’s ulcer)
- genetic conditions e.g. xeroderma pigmentosum, oculocutaneous albinism
9
Q
What is the management for squamous cell carcinoma?
A
Surgical excision with 4mm margins if lesion <20mm in diameter.
If tumour >20mm then margins should be 6mm.
Mohs micrographic surgery may be used in high-risk patients and in cosmetically important sites.
10
Q
What is Eczema herpeticum?
A
Severe primary infection of the skin by herpes simplex virus 1 or 2.
rarely it is caused by coxsackie virus.
11
Q
What are the features of eczema herpeticum?
A
- Rapidly progressing painful rash.
- Monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1-3 mm in diameter are typically seen.
- As it is potentially life-threatening children should be admitted for IV aciclovir.
12
Q
What is Pemphigus vulgaris?
A
Autoimmune disease caused by antibodies directed against desmoglein 3, a cadherin-type epithelial cell adhesion molecule. It is more common in the Ashkenazi Jewish population.
13
Q
What are the features of pemphigus vulgaris?
A
- mucosal ulceration is common and often the presenting symptom. - Oral involvement is seen in 50-70% of patients
- skin blistering - flaccid, easily ruptured vesicles and bullae. Lesions are typically painful but not itchy. These may develop months after the initial mucosal symptoms. Nikolsky’s describes the spread of bullae following application of horizontal, tangential pressure to the skin
- Acantholysis on biopsy
14
Q
What is the management of Pemphigus vulgaris?
A
PO steroids
immunosuppressants
15
Q
What is pellagra?
A
Caused by nicotinic acid (niacin) deficiency. The classical features are the 3 D’s - dermatitis, diarrhoea and dementia.
- may occur as a consequence of isoniazid therapy
- more common in alcoholics
16
Q
What are the features of pellagra?
A
- dermatitis (brown scaly rash on sun-exposed sites - termed Casal’s necklace if around neck)
- diarrhoea
- dementia, depression
- death if not treated
17
Q
What is the management for chronic psoriatic plaques?
A
- regular emollients may help to reduce scale loss and reduce pruritus
first-line: potent corticosteroid applied once daily + vitamin D analogue applied once daily
should be applied separately, one in the morning and the other in the evening)
for up to 4 weeks as initial treatment
second-line: if no improvement after 8 weeks then offer:
a vitamin D analogue twice daily
third-line: if no improvement after 8-12 weeks then offer either:
a potent corticosteroid applied twice daily for up to 4 weeks, or
a coal tar preparation applied once or twice daily
short-acting dithranol can also be used
18
Q
What are the investigations for venous ulcers?
A
- ankle-brachial pressure index (ABPI) is important in non-healing ulcers to assess for poor arterial flow which could impair healing
- a ‘normal’ ABPI may be regarded as between 0.9 - 1.2. Values below 0.9 indicate arterial disease. Interestingly, values above 1.3 may also indicate arterial disease, in the form of false-negative results secondary to arterial calcification (e.g. In diabetics)
19
Q
What is the management for venous ulcers?
A
- compression bandaging, usually four layer (only treatment shown to be of real benefit)
- oral pentoxifylline, a peripheral vasodilator, improves healing rate
- small evidence base supporting use of flavinoids
- little evidence to suggest benefit from hydrocolloid dressings, topical growth factors, ultrasound therapy and intermittent pneumatic compression
20
Q
What are the features of zinc deficiency?
A
- acrodermatitis: red, crusted lesions
- acral distribution
- peri-orificial
- perianal
- alopecia
- short stature
- hypogonadism
- hepatosplenomegaly
- geophagia (ingesting clay/soil)
- cognitive impairment
21
Q
What is pyoderma gangrenosum?
A
- rare, non-infectious, inflammatory disorder
- uncommon cause of very painful skin ulceration
- may affect any part of the skin, but the lower legs are the most common site.
- neutrophilic dermatoses characterised by dense infiltration of neutrophils in the affected tissue and this is often seen on biopsy
22
Q
What are the features of pyoderma gangrenosum?
A
- location
- typically on the lower limb
- soften at the site of a minor injury as in this patient’s case and this is known as pathergy
- initial features:
- usually starts quite suddenly
- small pustule, red bump or blood-blister
- later features:
- the skin then breaks down resulting in an ulcer which is often painful
- the edge of the ulcer is often described as purple, violaceous and undermined.
- ulcer itself may be deep and necrotic
- may be accompanied by systemic symptoms e.g. fever, myalgia
23
Q
What are the causes of pyoderma gangrenosum?
A
- idiopathic in 50%
- inflammatory bowel disease in 10-15%
- rheumatological
- rheumatoid arthritis
- SLE
- haematological
- myeloproliferative disorders
- lymphoma
- myeloid leukaemias
- monoclonal gammopathy (IgA)
- granulomatosis with polyangiitis
- primary biliary cirrhosis
24
Q
How is pyoderma gangrenosum diagnosed?
A
- often made by the characteristic appearance, associations with other diseases, the presence of pathergy, histology results and when other diseases have been ruled out
- histology is not specific and can vary depending on the time and site of the specimen but may be helpful in ruling out other causes of an ulcer.
25
What is the management for pyoderma gangrenosum?
- risk of rapid progression is high in most patients so oral steroids as first-line treatment
- other immunosuppressive therapy, for example, ciclosporin and infliximab, have a role in difficult cases
- any surgery should be postponed until the disease process is controlled on immunosuppression to risk worsening of the disease (pathergy)
26
What are the features of systemic mastocytosis?
- neoplastic proliferation of mast cells
- urticaria pigmentosa - produces a wheal on rubbing (Darier's sign)
- flushing
- abdominal pain
- monocytosis on the blood film
- diagnosis = raised serum tryptase levels, urinary histamine
27
What is the treatment for scabies?
- Permethrin cream, applied to all skin then rinsed after 12 hours is the current 1st line treatment for scabies.
- malathion 0.5% is second-line
- give appropriate guidance on use (see below)
- pruritus persists for up to 4-6 weeks post eradication
28
What is the treatment for crusted Norwegian scabies?
Ivermectin and isolation
29
What are the features of Scabies?
- caused by the mite Sarcoptes scabiei laying its eggs in the stratum corneum
- widespread pruritus
- linear burrows on the side of fingers, interdigital webs and flexor aspects of the wrist
- in infants, the face and scalp may also be affected
- secondary features are seen due to scratching: excoriation, infection
30
What are the features of lichen planus?
- itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms
- rash often polygonal in shape, with a 'white-lines' pattern on the surface (Wickham's striae)
- Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
- oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
- nails: thinning of nail plate, longitudinal ridging
31
What drugs can cause an eruption of lichen planus?
- gold
- quinine
- thiazides
32
What is the management 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
33
What is Pityriasis versicolor?
Pityriasis versicolor, also called tinea versicolor, superficial cutaneous fungal infection caused by Malassezia furfur (formerly termed Pityrosporum ovale).
34
What are the features of Pityriasis versicolor?
- 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
35
What is the treatment for Pityriasis versicolor?
- 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
36
What factors may predispose you to pityriasis versicolor?
- occurs in healthy individuals
- immunosuppression
- malnutrition
- Cushing's
37
What is Molluscum contagiosum?
common skin infection caused by molluscum contagiosum virus (MCV), a member of the Poxviridae family.
Transmission occurs directly by close personal contact, or indirectly via fomites (contaminated surfaces) such as shared towels and flannels.
The majority of cases occur in children (often in children with atopic eczema), with the maximum incidence in preschool children aged 1-4 years.
38
What are the features of molluscum contagiosum?
pinkish or pearly white papules with a central umbilication, which are up to 5 mm in diameter.
Lesions appear in clusters in areas anywhere on the body (except the palms of the hands and the soles of the feet).
In children, lesions are commonly seen on the trunk and in flexures, but anogenital lesions may also occur.
In adults, sexual contact may lead to lesions developing on the genitalia, pubis, thighs, and lower abdomen.
Rarely, lesions can occur on the oral mucosa and on the eyelids.
39
What is the management of Molluscum contagiosum?
Self-care:
- self-limiting, usually resolves within 18 months
- lesions are contagious but exclusion from school not required.
- avoid sharing clothing/towels/flannels etc
If lesions troublesome/unsightly:
- Squeezing (with fingernails) or piercing (orange stick) lesions may be tried, following a bath. Treatment should be limited to a few lesions at one time
- Cryotherapy may be used in older children or adults
- Eczema or inflammation can develop around lesions prior to resolution. Treatment may be required if:
* Itching is problematic; prescribe an emollient and a mild topical corticosteroid (e.g. hydrocortisone 1%)
* The skin looks infected (e.g. oedema, crusting); prescribe a topical antibiotic (e.g. fusidic acid 2%)
40
What is granuloma annulare?
- papular lesions that are often slightly hyperpigmented and depressed centrally
- typically occur on the dorsal surfaces of the hands and feet, and on the extensor aspects of the arms and legs
- A number of associations have been proposed to conditions such as diabetes mellitus but there is only weak evidence for this
41
What is Porphyria cutanea tarda?
- most common hepatic porphyria
- inherited defect in uroporphyrinogen decarboxylase or caused by hepatocyte damage e.g. alcohol, hepatitis C, oestrogen.
42
What are the 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
43
What are the 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
44
What is the management of porphyria cutanea tarda?
- chloroquine
- venesection
* preferred if iron ferritin is above 600 ng/ml
45
What skin disorder is associated with gastric cancer?
Acanthosis nigricans
46
What skin disorder is associated with lung cancer?
Erythema gyratum repens
Dermatomyositis
Acquired hypertrichosis lanuginosa
47
What skin disorder is associated with lymphoma?
Acquired ichthyosis
Erythroderma
48
What skin disorder is associated with ovarian cancer?
Acquired hypertrichosis lanuginosa
49
What skin disorder is associated with gastrointestinal cancer?
Acquired hypertrichosis lanuginosa
50
What skin disorder is associated with pancreatic cancer?
Migratory thrombophlebitis
51
What skin disorder is associated with Glucagonoma?
Necrolytic migratory erythema
52
What skin condition is associated with myeloproliferative disorders?
Pyoderma gangrenosum (bullous and non-bullous forms)
53
What skin condition is associated with haematological malignancies?
Sweet's syndrome
54
What skin condition is associated with oesophageal cancer/
Tylosis
55
What is dermatitis herpetiformis?
Autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.
More than 90% of patients exhibit small bowel biopsy findings consistent with some degree of gluten-sensitive enteropathy.
56
What are the features of dermatitis herpetiformis and how is it diagnosed?
- itchy, vesicular skin lesions on the extensor surfaces (e.g. elbows, knees, buttocks)
- skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis
57
What is the management of dermatitis herpetiformis?
gluten-free diet
dapsone
58
What is livedo reticularis?
Livedo reticularis describes an purplish, non-blanching, reticulated rash caused by obstruction of the capillaries resulting in swollen venules.
Causes:
idiopathic (most common)
polyarteritis nodosa
systemic lupus erythematosus
cryoglobulinaemia
antiphospholipid syndrome
Ehlers-Danlos Syndrome
homocystinuria
59
What are the adverse effects of isotretinoin?
- teratogenicity
* females should ideally be using two forms of contraception (e.g. Combined oral contraceptive pill and condoms)
- dry skin, eyes and lips/mouth
* the most common side-effect of isotretinoin
- low mood
- raised triglycerides
- hair thinning
- nose bleeds (caused by dryness of the nasal mucosa)
- intracranial hypertension: isotretinoin treatment should not be combined with tetracyclines for this reason
- photosensitivity
60
What is melasma?
- symmetrical hyperpigmented patches typically affecting the face, particularly the cheeks, forehead, upper lip, and nose
- Typically occurs in pregnancy due to increased levels of oestrogen and progesterone stimulating melanocytes.
61
What is bullous pemphigoid?
- Autoimmune condition causing sub-epidermal blistering of the skin. - secondary to the development of antibodies against hemidesmosomal proteins BP180 and BP230.
62
What are the features of bullous pemphigoid?
- itchy, tense blisters typically around flexures
- the blisters usually heal without scarring
- stereotypically no mucosal involvement (i.e. the mouth is spared)
in reality around 10-50% of patients have a degree of mucosal involvement.
- more common in elderly
63
What are the skin biopsy findings in bullous pemphigoid?
immunofluorescence shows IgG and C3 at the dermoepidermal junction
64
What is the management for 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
65
What skin disorders are associated with diabetes?
Necrobiosis lipoidica
Infection (candidiasis, staphylococcal)
Neuropathic ulcers
Vitiligo
lipoatrophy
Granuloma annulare
66
What is the inheritance pattern of Hereditary haemorrhagic telangiectasia?
Autosomal dominant pattern of inheritance and age-related penetrance (majority of individuals manifesting symptoms such as recurrent epistaxis (nosebleeds) during adolescence)
67
What is the diagnostic criteria for Hereditary Haemorrhagic 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
68
What are predisposing factors for keloid scar formation?
- ethnicity: more common in people with dark skin
- occur more commonly in young adults, rare in the elderly
- common sites (in order of decreasing frequency): sternum, shoulder, neck, face, extensor surface of limbs, trunk
69
What is the treatment for keloid scars?
- early keloids may be treated with intra-lesional steroids e.g. triamcinolone
- excision is sometimes required but careful consideration needs to given to the potential to create further keloid scarring
70
What are the features of pityriasis rosea?
- acute, self-limiting rash which tends to affect young adults.
- herpes hominis virus 7 (HHV-7) may play a role.
- herald patch (usually on trunk)
- followed by erythematous, oval, scaly patches which follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer. This may produce a 'fir-tree' appearance
- self limiting usually resolves in 6-12 weeks
71
What are causes of hypertrichosis (androgen-independent hair growth)?
- drugs: minoxidil, ciclosporin, diazoxide
- congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis
- porphyria cutanea tarda
- anorexia nervosa
72
What conditions are associated with yellow nail syndrome?
- congenital lymphoedema
- pleural effusions
- bronchiectasis
- chronic sinus infections
73
What is erythema ag igne?
Erythema ab igne is a skin disorder caused by over exposure to infrared radiation. Characteristic features include reticulated, erythematous patches with hyperpigmentation and telangiectasia. A typical history would be an elderly women who always sits next to an open fire.
If the cause is not treated then patients may go on to develop squamous cell skin cancer.
74
What are the features of tines capitis?
- Scalp ringworm
- scarring alopecia mainly seen in children
- if untreated a raised, pustular, spongy/boggy mass called a kerion may form
- most common cause is Trichophyton tonsurans in the UK and the USA
- may also be caused by Microsporum canis acquired from cats or dogs
- diagnosis: lesions due to Microsporum canis green fluorescence under Wood's lamp - most useful investigation is scalp scrapings
- management: oral antifungals: terbinafine for Trichophyton tonsurans infections and griseofulvin for Microsporum infections. Topical ketoconazole shampoo should be given for the first two weeks to reduce transmission
75
What are the features of keratoacanthomas?
benign epithelial tumour
more common with advancing age and rare in young people.
Features - said to look like a volcano or crater
initially a smooth dome-shaped papule
rapidly grows to become a crater centrally-filled with keratin
Spontaneous regression of keratoacanthoma within 3 months is common, often resulting in a scar. Such lesions should however be urgently excised as it is difficult clinically to exclude squamous cell carcinoma. Removal also may prevent scarring.
76
What are some causes of scarring alopecia?
- trauma, burns
- radiotherapy
- lichen planus
- discoid lupus
- tinea capitis*
77
What are some causes of non-scarring alopecia?
- male-pattern baldness
- drugs: cytotoxic drugs, carbimazole, heparin, oral contraceptive pill, colchicine
- nutritional: iron and zinc deficiency
- autoimmune: alopecia areata
telogen effluvium
- hair loss following stressful period e.g. surgery
- trichotillomania
78
What are the features of polymorphic eruption in pregnancy?
- pruritic condition associated with last trimester
- lesions often first appear in abdominal striae
- management depends on severity: emollients, mild potency topical steroids and oral steroids may be used
79
What are the features of pemphigoid gestationis?
- pruritic blistering lesions
often develop in peri-umbilical region, later spreading to the trunk, back, buttocks and arms
- usually presents 2nd or 3rd trimester and is rarely seen in the first pregnancy
- oral corticosteroids are usually required
80
What is Koebner phenomenon and what conditions are associated with it?
skin lesions that appear at the site of injury
- psoriasis
- vitiligo
- warts
- lichen planus
- lichen sclerosus
- molluscum contagiosum
81
What is the management for hirsutism?
- advise weight loss if overweight
- cosmetic techniques such as waxing/bleaching - not available on the NHS
- consider using combined oral contraceptive pills such as co-cyprindiol (Dianette) or ethinylestradiol and drospirenone (Yasmin). Co-cyprindiol should not be used long-term due to the increased risk of venous thromboembolism
- facial hirsutism: topical eflornithine - contraindicated in pregnancy and breast-feeding
82
What is the most important prognostic factor in malignant melanoma?
Depth of tumour
83
What are the features of Necrobiosis lipoidica diabeticorum?
- shiny, painless areas of yellow/red skin typically on the shin of diabetics
- often associated with telangiectasia
84
What are some causes of Steven Johnson Syndrome?
- penicillin
- sulphonamides
- lamotrigine, carbamazepine, phenytoin
- allopurinol
- NSAIDs
- oral contraceptive pill
85
What are the features of Steven Johnson Syndrome?
- typically maculopapular rash with target lesions being characteristic
may develop into vesicles or bullae
- Nikolsky sign is positive in erythematous areas - blisters and erosions appear when the skin is rubbed gently
- mucosal involvement
- systemic symptoms: fever, arthralgia
86
