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)
Alopecia
Alopecia may be divided into scarring (destruction of hair follicle) and non-scarring (preservation of hair follicle)
Scarring alopecia
- trauma, burns
- radiotherapy
- lichen planus
- discoid lupus
- tinea capitis*
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 (hair pulling)
*scarring would develop in untreated tinea capitis if a kerion develops
TB
Possible skin disorders
- lupus vulgaris (accounts for 50% of cases)
- erythema nodosum
- scarring alopecia
- scrofuloderma: breakdown of skin overlying a tuberculous focus
- verrucosa cutis
- gumma
Lupus vulgaris is the most common form of cutaneous TB seen in the Indian subcontinent. It generally occurs on the face and is common around the nose and mouth. The initial lesion is an erythematous flat plaque which gradually becomes elevated and may ulcerate later
Eczema: diagnosis
UK Working Party Diagnostic Criteria for Atopic Eczema
An itchy skin condition in the last 12 months
Plus three or more of;
* onset below age 2 years**
* history of flexural involvement*
* history of generally dry skin
* personal history of other atopic disease**
* visible flexural dermatitis
- *not used in children under 4 years
- **or dermatitis on the cheeks and/or extensor areas in children aged 18 months or under
- ***in children aged under 4 years, history of atopic disease in a first degree relative may be included
Pityriasis rosea
Overview
- cause unknown, herpes hominis virus 7 (HHV-7) a possibility
- tends to affect young adults
Features
- 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 ‘firtree’ appearance
-skin lesions seen in pityriasis rosea are generally larger than those found in guttate psoriasis and scaling is typically confined to just inside the edges
Management
* self-limiting, usually disappears after 4-6 weeks
Contact dermatitis
There are two main types of contact dermatitis
- irritant contact dermatitis: common – non-allergic reaction due to weak acids or alkalis (e.g. detergents). Often seen on the hands. Erythema is typical, crusting and vesicles are rare
- allergic contact dermatitis: type IV hypersensitivity reaction. Uncommon – often seen on the head following hair dyes. Presents as an acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself. Topical treatment with a potent steroid is indicated
Cement is a frequent cause of contact dermatitis. The alkaline nature of cement may cause an irritant contact dermatitis whilst the dichromates in cement also can cause an allergic contact dermatitis
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, oestrogens
Features
- classically presents with photosensitive rash with blistering and skin fragility on the face and dorsal aspect of hands (most common feature)
- hypertrichosis
- hyperpigmentation
Investigations
* urine: elevated uroporphyrinogen and pink fluorescence of urine under Wood’s lamp
Management
- chloroquine
- venesection
Pemphigus vulgaris
Blisters/bullae
- no mucosal involvement: bullous pemphigoid
- mucosal involvement: pemphigus vulgaris
Pemphigus vulgaris is an autoimmune disease caused by antibodies directed against desmoglein, a cadherintype epithelial cell adhesion molecule. It is more common in the Ashkenazi Jewish population
Features
- 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
Management
- steroids
- immunosuppressants
Psoriasis: exacerbating factors
- trauma
- alcohol
- drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors
- withdrawal of systemic steroids
Fungal nail infections
Onychomycosis is fungal infection of the nails. This may be caused by
- dermatophytes – mainly Trichophyton rubrum, accounts for 90% of cases
- yeasts – such as Candida
- non-dermatophyte moulds
Features
- ‘unsightly’ nails are a common reason for presentation
- thickened, rough, opaque nails are the most common finding
Investigation
- nail clippings
- scrapings of the affected nail
Management
- treatment is successful in around 50-80% of people
- diagnosis should be confirmed by microbiology before starting treatment
- dermatophyte infection: oral terbinafine is currently recommended first-line with oral itraconazole as an alternative. Six weeks – 3 months therapy is needed for fingernail infections whilst toenails should be treated for 3 – 6 months
- Candida infection: mild disease should be treated with topical antifungals (e.g. Amorolfine) whilst more severe infections should be treated with oral itraconazole for a period of 12 weeks
