Dermatology Flashcards
Discuss a general approach to an unknown rash
1: time of onset
2) historical features
- new potential allergens
- change over time
- progression waxing or waning
- Associated symptoms - pain pruritis, fever, sexual history, occupation or hobbies
3) medical hisotry
4) primary lesions
5) secondary lesions
6) distribution of the lesions
7) systemic illness
8) diagnoistic tests
9) category of rash
- infectious
- immune
- vascular
- allergic
- malignancy
10) treatment
Differentiate primary and secondary lesions
Primary lesions arise as a direct result of the disease process
Secondary lesions aris from subsequent factros such as scratching, treatment, healing or complicating infection.
Describe primary lesions
1) Macule - flat circumscribed pigmented area <0.5cm
2) Patch - flat circumscribed pigmented area >0.5cm
3) Papule -elevated solid palpable lesion variable colour - <0.5cm
4) plaque - elevated solid palpable lesions variable colour > 0.5cm
5) Nodule - solid palpable subcutaneous lesions <0.5cm in diameter
6) tumor - solid palpable subcutaneous lesiosn >0.5cm
7) vesicle elevated thin walled circumscribed clear fluid filled lesion <0.5cm in diamter
8) Pustule elevated circumscribed purulent fluid filled lesion
9) Petechia - flat eryhtematous or violaceous non blanching lesios <0.5cm in diamter
10) purpura - erythemaotus or violaceous non blanching leiosns may be palpable >0.5cm
Describe secondary lesions
1) Scale - thickened area of keratinized epithelium
2) Crust -dried area of plasma proteins resulting from inflamation
3) fissures - deep cracks in the skin surface extending into the dermis
4) Erosions - disruption of surface eiptherlium usually linear traumatic
5) ulcer deep erosion extending into dermis
7) scar dense collection of collagen
8) excoriation: linear erosions typically secondary to scratching or rubbing
9) Lichenification - abnormally dense layer of keratinzed epidermal cells
10) hyperpigmentation
Describe tinea corporis
Refers to superficial dermatophytic infection of the skin and or nails usually by the trichophyton organism.
Commonly referred to as ringworm infection presents as a sharply marginated annular lesion with raised or vesicular margins and central clearing
Usually respond well to topical antifungal creams such as clotrimazole
Ketoconazole 2% cream applied once dailey
Miconazole 2% cream twice dailey for 4 weeks
Describe tinea capitus
Fungal infection of the scalp. Although it is often seen in paediatric patients 6-10 years old tinea capitus is also seen in adults
Alopecia may be seen typically with thickned scaly scalp. Broken hairs resembling black dots near the saclp may be seen
May be transmitted by close child to child contact and contact with household pets hats, combs barber shears and similar items
Systemic therapy is required for tinea capitus due to fungal invasion of the hair follice.
Oral terbinafine 250mg orally OD for 4 weeks
-20-40 kg 125mg
>20kg -62.5mg
Describe Kerion
A kerion is a fungal infection affecting hair follicles that is characterized by intense inflammation and a boggy erythematous mass typically affecting the scalp
Most common in children and in African AMericans- local alopecia and scarring can ensure
Kerions are terated the same as tinea capitus with systemic antifungals agents for 6-8 weeks. If abcterial superinfection exists an antibiotic is added. Clinda if MRSA or Bactrim
Surgical drainage of Kerions are not helpful and should be avoided
Describe tinea unguium
Oncyomycosis
- loosening of the nail plate form the nail bed
- yellow discolouration of the nale
Describe tinea cruris
Groin and gluteal celft
Describe oral candidiasis
Most common climical expression of candida. It is common in newborns, elder persons, immunosuppressed or persons wearing dentures.
It appears as patches of white or gray friable material covering an erythematous base on the buccal mucosa gingiva toungue palate or tonsils.
DDX of candidiasis include lichen planus (which unlike candida is not easily scraped off) or hairly leukoplakia
Oral mucous membrane infection is an AIDS defining illness
Treatment for oral candidiasis may be undertaken with topical antifungal agents
-nystatin liquid 100000 units/ml 1ml topically than swallowed QID after feeding for 7-14 days
Oesophageal candidiasis will require systemic treatment
-fluconazole 200mg for first dose than 100mg dailey for 14-21 days
Discuss treatment of vulvovaginal candidiasis
Topical clotrimazole 1% vaginal cream once dailey at bedtime for 6 nights
or if not tolerating topical
One dose of fluconazole 150mg orally as a single dose
Discuss scabies infestations
Scabies mites can live off the human host for 3 days
Scabies present with intense pruritus and rash which usually develop after 1-8 weeks following exposure. Typically it is worst at night.
Clinical findings incldue small papules or pustules and small raised or flattened burrows. Distributed between the digital webs side of the fingers and volar aspects of the wrist and alteral palms, trunk elbows axillae scrotum penis and the areola in women.
In crusted sabies hyperkaratotic plaques develop diffusely often on the plamar and plantar regions. Immunodeficient patients are at risk for crusted scabies.
First line treatment of scabies is topical permethrin 5% – applied from the neck down covering all areas of the body including under the nails in the umbilicus around teh nipple and genitals. Face and scalp should be treated in infants and young children. Preferably it should be applied prior to bedtime left on overnight and then washed off 8-12 hours later. A second treatment should be administered in 1-2 weeks..
Equally important in the treatment is the decontamination of the clothing bed lines and towels by washing them in hot water and hot machine drying.
Permethrin 1% is also affective for headlice and genital lice
Discuss dermatitis
Inflammatory reaction of the skin to a chemical physical or biological agent which acts as an irritant or allergic sensitizer
Allergic contact dermatitis is a form of delayed hypersensitivty mediated by lymphocytes sensitized by the contact of the allergen to the skin. It is much less common than irritant contact
THe primary lesions of contact dermaitits are papules, vesciles and bullae on an erythematous base. Streaky linear intensely pruritic lesions are characteristic. Normally in a pattern in the region in contact with the allergne.
Treatment include avoidance of the irritant or allergen and treatment of inflammation. Low potency topical steroid creams may be applied to erythematous areas around natural orifices and medium potency can be used elsewhere.
Describe drug reactions
The most common eruptions are a morbilliform rash, urticaria, or fixed drug eruptions. More severe reaction may include vasculitis, erythema nodosum, angiooedema anaphylasis, stevens jhonson syndrome TEN, blistering dermatosis, drug induced lupus
Drug reactions often appear within 4-21 days after the drug is taken. Skin lesions may appear after a drug has been discontinued and may rowsen if the drug or metbaolite persist in the system.
Fixed drug reactions appear and recur at the same anatomic site after repeated exposure to the same drug
Treatment of drug eruptions beings with discontinuation of the inciting agent - most will fade wihtin 1 week of discontinuation, Antihistamines and steroids may be indicated.
Define morbilliform
The term morbilliform means measles-like because of the development of a maculopapular erythematous rash that becomes confluent
Discuss Atopic dermatitis
Eczema Atopic dermatits is an inflammatory skin condition. Diagnostic criteria include itchy skin plus three or more of the following -History of flexure involvement -generalised dry skin in the past year -histroy of asthma or hay fever -onset of rash before 2 years old -flexural dermatitis
Skin lesions generally appear as inflammatory thickened papular or papulovesicular lesions. The skin is typically dry and may b e scaly but in its acute phase may also be vesicular weeping or oozing.
Most common in antecubital or popliteal flexion areas, neck face and chest.
Intence pruritus is a hallmark of atopic dermaitits. During flares itch and failure of routine treatments are common presentation. Patients may also present with secondary infections. Repeated rubbing and scratching produce lichenifications.
Topical steroids are the cornerstone of therapy and are often best prescribed in ointment form. Approximately 80% of patients have improvement of symptoms with topical steroid treatment.
Skin dryness can be treated with lubricating ointments such as vaseline
Discuss disposition for eczema patients
Inpatient admission should be considered for those with generalized erythema and exfoliation or intractable itching in that skin breakdown and sever secondary abcterail or viral skin infections.
Patients with atopic dermatitis are suscepetiable to infection and colinization by a variety of organisms due to defective skin barrier and fucntion. Wide spread disseminated viral infections such as escema molluscum, vaccinatum or herpticum and recureent staph pustolosis are especially concerning and should be treated with antiinfectives as needed.
Discuss pityriasis rosea
Mild skin eruptions predominanty found in children and young adults. Ages 10-35 years are commonly affected
Clinical presentation includes multiple pink or pigmented oval papules or plaques 1-2cm in diameter on the trunk and proximal extremities.
Self limiting resolving in 8-12 weeks
Calamine lotion for pruitis
Discuss Erythema multiforme
Considered to be a hypersensitivity reaction and it may be caused by a drug reaction. Infections account for 90% -Viral (HSV, hepatitis, flu a, CMV) -Fungal (dermatophytosis, histoplasmos) -Bacteral (strep and TB) -Collagen vascular disorder (RA, SLE, periarteritis nodosa) -Pregnancy -multiple malignancies -Drug reactions
Erythema multiforme is an acute usually self limit disease
It is charachterized by skin liesions that are erythematous or violaceous maculues, papules, vesciles or bullae
Theire distribution is often symmetrical most commonly involving the soles and palms, the back of the hands or feet and the extensor surfaces of the extremities.
The target lesions with three zones of color is the hallmark of erythema multiforme. It is a central darke papule or vescile that is surroudned by a pale zone and a halo of erythema,
Management
- withdraw offending agent
- mild cases with nil systemic features typically spontaneously resolve in 2-3 weeks
- those with lesiosn on the trunk and those who are immunocompromised especially those with mutiple lesiosn require a course of systemic steroids for 14-21 days.
- Patients with mucous membrnae involvement systemic symptoms or vesicle fomration raise concern for Steven johnson sydnrome
Discuss SJS and TENS
Considered a continuous sprectum of the same disease, an immune complex mediated hypersensitivty reaction.
SJS is considered a mild fomr of TENS with less than 10% BSA. TENS includes patients with more than 30% BSA
The main feature of non staphylococcla induced toxic epidermal necrolysis is the seperation of large sheets of epidermis
Discuss Causes of SJS and TENS
Drugs - account for 90% of cases in adults
- More common in HIB infection
- sulphonamides
- betalactams: penicllins and cephalosporins
- omeprazoles
- allopurional
- anticonvulsants (classic ones)
- dapsone
Describe clinical features of TENS
Commonly beings with prodromal symptoms such as fever malaise rhinitis sore thorat and myalgisa.
These are vollowed by the abrupt development of macular rash taht appear as target lesions. The extremities are commonly involved although any area may be affected. THe exanthem becomes confluent and dermal epidermal dissociation ensues. Nikloskys sign is presnet and the skin is commonly more painful to touche
Mucous memrbane invovemnt may occur with erythema, blistering sloughing or necrosis. Involvement of the conjunctivae and cornea may lead to permanent scarring and blindness
Renal GIT or resp tract lesions may develop leading ot haematuria, diarrhoea bronchitis or pneumonia.
Discuss management of TENS or SJS
Discontinuation of the offending agent and supportive care, inclduing hydration prevention of secondary infection and expert wound care.
This is usually best accomplsihed in a centre with burn care expertise.
Systemic steroids are contraindicated - nil improvement and may mask signs of sepsis.
-IVIG considered
-ciclosproin
-infliximap
-plasmapheresis
List DDX of blistering rashes
- Sunburn
- Kawasaki syndrome
- TSS
- Staph scalded skin
- Erythema multiforme-SJS-TENS
- Pemphigoid
- pemphigus
- insect bites
- mustard gas
Describe erythema nodosum
Inflammatory reaction of the dermis and adipose tissue that present with painful erythematous or violaceous subcutaneous nodules.
These painful nodules occur most commonly over the anterior tibia but may also be seen on the arms or body.
Fever arthralgia of the ankles and knees may precede the rash.
A number of disease are associated with erythema nodosum
- drug reactions
- sarcoidosis
- coccidioidomycosis
- TB
- ulcerative collitis
- infection with strep
Management begins with treatment of the underlying etiology
CXR may be helpful in ruling out sarcoid TB or pulmonary fungal infection.
Aspirin in a dosage of 650mg Q4hourly or other NSAIDS may also afford some relief.
Usually slef limiting process that resolves in 3-8 weeks,
Discuss Bullous pemphigoid
- Autoimmune blistering disorder that most commonly affects geiatric patients
- Clinical manifestations are often pruritus and generalsied blistering of the skin
- Nikolsky sign is -ve
Blisters
- have tense roof
- do not expand or rupture under pressure
- may be itchy
- may be extensive
Management consists of
- systemic steroids pednisone 0.5mg/kg daileu - usually rapidly effective
- azathioprine in steroid resistant cases
Discuss Bullous vulgaris
Caused by antiboides to keratinocyte adhesions molecules causing loss of cellular adhesions. May be precipirated by
- penicillamine
- Ace inhibitors
Affects both sexes and is most common in ages 40-60
More prevalent in people of Jewish, Mediteranean or south Asian descent
The typical skin lesions are small flaccid bullae that break easily forming superficial erosions and crusted ulcerations.
Nikolsky sgins is present and is characteristic of the disease.
Many patients also have oral lesions (50-60%)- the oral lesions typically antedate the cutaneous leiosns by several months.
Paraneoplastic pemphigus is associated with B cell lymphoma or CLL
Management
- systemic corticosteroids
- doses greater than 1mg/kg no longer recommended
- Add azathioprine 4mg/kg if steroids not effective
- rituximab causes remission in 70% by 6 months and 90% by 2 years.
Describe psoriasis
Affects 3% of the population
-more common in caucasians
Autoimmune disease - lesiosn are populated with large numbers of activated T- cells
- drive the inflammatory process
- cause dysmaturation of epidermal cells
- impair skin fucntion
Complications
- increased water loss from the epidermis
- increased susceptibility to physical and chemical irritation
- pain from fissures and cracks
- in severe
- — risk of steatohepatitis and cirrhosis
- —increased risk fo skin cancer
Describe clinical finding in psoriasis
Plaque 80-90%
- bilateral
- often symmetrcial
- sharply demarcated plaques
Describe management of psoriasis
Remove scales by soaking with water
Topcial steroids - betamethasone valerate than cover with plastic wrap and leafe overnight
Other topical therapy
- vitamin D
- retinoids
- tar
- dithranol
Systemic: when large areas of skin are involved or resistnat to topical therapy
- -Narrow band UVB
- Ciclosporin (usually clears psoriasis in 6-12 weeks, effective in maintaining disease remission, adverse effects usually limit the duraiton to 12-24 months)
- methotrexate
Describe BCC
Most common malignancy in australia
Most are related to sun exposure
Locations
- develop on sun exposed areas
- 80% on head and neck
Slow growing
Description
- Nodula
- pearly papule or nodule
- overlying telangiectases - beeding following minor trauma
- rolled edge with central depression
- occasional central crusting or ulceration
- occasionally appears like an enlarged pore or pit
Managemnet
- Cryosurgery
-topical photodynamic treatment
Surgery -excision with 3-4 mm margin
Describe SCC
Less common than BCC
aso associated with sun exposure
Appearance
- scaly surface
- irregular edge
- may be attached to deeper sturctures
- mor commonly bleed
- may ahve regional lymph node invovlement
Excision with 3-5mm margin
Describe melanoma
Rare before puberty
4% of all dermatologic cancers
causes 80% of deaths from cancer
Risk factors
- Family history
- multiple benign of dysplastic nevi
- previous melanoma
- immunosupression
- fair blue eyes
- sunburn as a child
Discuss features suggesitve of melanoma
A: asymmetry of lesion
B: irregular border
C: variation of colour within the lesion
D: >6mm
Recent appearance chagne in existing mole
ulceration or bleeding
satellite nodules
Discuss prongosis
Notorious for recurrence even after uears of apparent quiescnece
15% of patients with metastatic melaboma survive for 5 years
Mets
- liver
- lung
- brain - classically haemorrhagic
- skin
- retina
- myocardium
Poor progonstic features
- males
- increasing age
- thick lesions
- satellite nodules
- mets
Discuss management of melanoma
Wide excision with 1-2cm surrounding the lesion
- sentinel node biopsy
- interferon in selected cases
Discuss crusted scabies and its management
Can occur in the presence of conditions that compromise cellular immunity such as AIDS, Leprosy or lymphoma. This variant may also occur in older adults with Downs or the use of long term topical corticosteroids
High number of mites present
Begins with a poorly defined erythematous patches that quickly develop prominenet scale. If untreated the disease usually spread inexorably and mya eventually involve the entire integument. Scales becomes wartery
MANAGEMENT
- Use of Permethrin 5% cream + oral ivermectin 200mcg/kg/dose given for 3/5/7 nonconsecutive days depending on severity of infestaiton.
- Concomitant use of topical keratolytic creams may help to reduce crusting
Describe erythroderma
Atopic dermatici erythroderma is the most common form in chidlre and young adults but other causes are more common in middle age and in the elderly caused by:
1) drug eruption - including dress
2) atopipc dermatitis - 40%
3) psorasis
4) pityraissi rubra pilaris
Presents with diffuse erythema and scaling involving all or most of the skin surface (>90% be the most common definition) - it is a clinical sign and may be the presentation of a wide range of cutanous and systemic disease. Erythema may become generaliased in hours to days to weeks – exfloiation typically beings 2-6 days after the onset of erythema starts in the felxural areas and rapidly extends to the entire body surgace.
Describe DRESS
Severe adverse drug reaction characterised by extensive skin rash in association with visceral organ involvement, lymphadenopathy, eosinophilia and atypical lympocytosis.
Features
1) dermatitis - maculopapular eruption that may progress to a coalescing erythema - mucous involvement in 50%
2) fever >38.5
3) Haem
- eosinophilia >0.7/l
- leucocytosis
- neutrophilia
4) organ involvement
- liver most common – cholestatic or hetapocellur or mixed
- Kidney ranging from proteinuria to failure
- pulmonary -interstitial infiltrates and pleural effusion
- CVS- severe complication with poor prognosis 2-20% - presenting this LV dysfunction, hypotension and tachycardia
Removal of offending agent and supportive care
Describe pyoderma gangrenosum
Rapidly enlarging very painful ulcer. It is not an infection nor does it cause gangrene
It is associated with
- IBD
- RA
- Chronic active heptatits
- Granulomatosis with polyangitis
- leukaemia
Ulcer
- very painful
- starts suddenly after a minor injury
- it may start as a small pustule red bump or blood blister
- the skin then breaks down resulting in the ulcer which can deepen and widen rapidly – the edgrs are purple and undermined
Describe purpura fulminans and its DDX
Extreme thrombotic subtype of DIC marked by micvascular thrombosis causing skin necrosis
Bacterial infection 1) N meningitides - most common 2) HIB 3) Strep peumo especially post splenectomy 4) strep pyogenes 5) staph aueus 6) Gram -ve basilli Viral 1) VZV 2) West nile 3) Rubella Protozoa 1) Falciparum
Describe the SCORTEN score
1) Age <40
2) HR >120
3) presence of cancer or Haem malignancy
4) epidermal detachment involving body surface area >10%
5) BUN >10
6) glucose >14
7) Hco3 <20
0-1 motrality 3.2%
>5 90%
LIst DDX for peterchia
WITH SPLEENOMEGALY
1) non thrombocytopenic
- VWB
2) normal marrow
- Liver disease with portal hypertension
- Myeloproliferative disorders
- lymphoproliferative disorders
- hypersplenisis
3) abnormal marro
- Luekaemia
- lymphoma
- myeloid metaplasia
WITHOUT SPLENOMEGALY 1) Normal Marrow Immune -Idiopathic TP -drugs -infection Non-immune -vasculitis -DIC -HUS -TTP 2) Palpable purpura -PAN -HSP -Infective
