derm Flashcards
Systemic mastocytosis
neoplastic proliferation of mast cells
Features
- 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
impetigo
golden, crusted lesion on the border of lower lip
Rx
Limited, localised disease
* topical fusidic acid is first-line
* topical retapamulin is used second-line if fusidic acid has been ineffective or is not tolerated
* MRSA is not susceptible to either fusidic acid or retapamulin. Topical mupirocin (Bactroban) should therefore be used in this situation
Extensive disease
- oral flucloxacillin
- oral erythromycin if penicillin allergic
Sweet’s syndrome
AML
DM
Necrobiosis lipoidica Infection- candidiasis,staphylococcal Neuropathic ulcers Vitiligo Lipoatrophy Granuloma annulare
Acne rosacea
chronic skin disease of unknown aetiology
Features
- typically affects nose, cheeks and forehead
- flushing is often first symptom
- telangiectasia are common
- later develops into persistent erythema with papules and pustules
- rhinopehyma
- ocular involvement: blepharitis
Management
- topical metronidazole may be used for mild symptoms (i.e. Limited number of papules and pustules, no plaques)
- more severe disease is treated with systemic antibiotics e.g. Oxytetracycline
- recommend daily application of a high-factor sunscreen
- camouflage creams may help conceal redness
- laser therapy may be appropriate for patients with prominent telangiectasia
TEN
Features
- systemically unwell e.g. pyrexia, tachycardic
- positive Nikolsky’s sign: the epidermis separates with mild lateral pressure
Drugs known to induce TEN
- phenytoin
- sulphonamides
- allopurinol
- penicillins
- carbamazepine
- NSAIDs
Management
- stop precipitating factor
- supportive care, often in intensive care unit
- intravenous immunoglobulin has been shown to be effective and is now commonly used first-line
- other treatment options include: immunosuppressive agents (ciclosporin and cyclophosphamide), plasmapheresis
acanthosis nigricans
symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin
Causes
- gastrointestinal cancer
- insulin-resistant diabetes mellitus
- obesity
- polycystic ovarian syndrome
- acromegaly
- Cushing’s disease
- hypothyroidism
- familial
- Prader-Willi syndrome
- drugs: oral contraceptive pill, nicotinic acid
Pyoderma gangrenosum
- typically on the lower limbs
- initially small red papule
- later deep, red, necrotic ulcers with a violaceous border
- may be accompanied systemic symptoms e.g. Fever, myalgia
Causes
- idiopathic in 50%
- inflammatory bowel disease: ulcerative colitis, Crohn’s
- rheumatoid arthritis, SLE
- myeloproliferative disorders
- lymphoma, myeloid leukaemias
- monoclonal gammopathy (IgA)
- primary biliary cirrhosis
Management
- the potential for rapid progression is high in most patients and most doctors advocate oral steroids as first-line treatment
- other immunosuppressive therapy, for example ciclosporin and infliximab, have a role in difficult cases
Bullous pemphigoid
antibodies against hemidesmosomal proteins BP180 and BP230
-elderly
Features include
- itchy, tense blisters typically around flexures
- the blisters usually heal without scarring
- mouth is usually spared*
Skin biopsy
* immunofluorescence shows IgG and C3 at the dermoepidermal junction
Management
- referral to dermatologist for biopsy and confirmation of diagnosis
- oral corticosteroids are the mainstay of treatment
- topical corticosteroids, immunosuppressants and antibiotics are also used
psoriasis
Psoriasis is a common and chronic skin disorder. It generally presents with red, scaly patches on the skin although it is now recognised that patients with psoriasis are at increased risk of arthritis and cardiovascular disease.
Pathophysiology
- multifactorial and not yet fully understood
- genetic: associated HLA-B13, -B17, and -Cw6. Strong concordance (70%) in identical twins
- immunological: abnormal T cell activity stimulates keratinocyte proliferation. There is increasing evidence this may be mediated by a novel group of T helper cells producing IL-17, designated Th17. These cells seem to be a third T-effector cell subset in addition to Th1 and Th2
- environmental: it is recognised that psoriasis may be worsened (e.g. Skin trauma, stress), triggered (e.g. Streptococcal infection) or improved (e.g. Sunlight) by environmental factors
Recognised subtypes of psoriasis
- plaque psoriasis: the most common sub-type resulting in the typical well demarcated red, scaly patches affecting the extensor surfaces, sacrum and scalp
- flexural psoriasis: in contrast to plaque psoriasis the skin is smooth
- guttate psoriasis: transient psoriatic rash frequently triggered by a streptococcal infection. Multiple red, teardrop lesions appear on the body
- pustular psoriasis: commonly occurs on the palms and soles
Other features
- nail signs: pitting, onycholysis
- arthritis
Complications
- psoriatic arthropathy (around 10%)
- increased incidence of metabolic syndrome
- increased incidence of cardiovascular disease
- psychological distress
Lichen
- 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
Key points on Lichen planus:
Lichen planus is a skin disorder of unknown aetiology, most probably being immune mediated.
Features
- itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms
- rash often polygonal in shape, ‘white-lace’ 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
- nails: thinning of nail plate, longitudinal ridging
Lichenoid drug eruptions – causes:
- gold
- quinine
- thiazides
Management
- topical steroids are the mainstay of treatment
- extensive lichen planus may require oral steroids or immunosuppression
Lichen sclerosus
Lichen sclerosus was previously termed lichen sclerosus et atrophicus. It is an inflammatory condition which usually affects the genitalia and is more common in elderly females. Lichen sclerosus leads to atrophy of the epidermis with white plaques forming
Features
* itch is prominent
A biopsy is often performed to exclude other diagnoses
Management
- topical steroids and emollients
- increased risk of vulval cancer
Skin disorders associated with pregnancy
Polymorphic eruption of 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
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
Causes of hypertrichosis
- drugs: minoxidil, ciclosporin, diazoxide
- congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis
- porphyria cutanea tarda
- anorexia nervosa
Hirsutism
Polycystic ovarian syndrome is the most common causes of hirsutism. Other causes include:
- Cushing’s syndrome
- congenital adrenal hyperplasia
- androgen therapy
- obesity: due to peripheral conversion oestrogens to androgens
- adrenal tumour
- androgen secreting ovarian tumour
- drugs: phenytoin
Assessment of hirsutism
* Ferriman-Gallwey scoring system: 9 body areas are assigned a score of 0 – 4, a score > 15 is considered to indicate moderate or severe hirsutism
Management of 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
topical steroid
Mild
Hydrocortisone 0.5-2.5%
mod
- Betamethasone valerate 0.025% (Betnovate RD)
- Clobetasone butyrate 0.05% (Eumovate)
potent
- Fluticasone propionate 0.05% (Cultivate)
- Betamethasone valerate 0.1% (Betnovate)
very potent
Clobetasol propionate 0.05% (Dermovate)
