Dermatology Flashcards
What type of condition is eczema?
Chronic atopic
What causes eczema?
Defects in the normal continuity of the skin barrier, leading to inflammation
At what stage does eczema usually present?
In infancy
How does eczema usually present?
Dry, red, itchy sore patches of skin over flexor surfaces
What are the main areas of the body where eczema presents?
Flexor surfaces- inside of elbows and knees
Face and neck
What is the pathophysiology of eczema?
Defects in the skin barrier provide an entrance for irritants, microbes and allergens that create an immune response, resulting in inflammation
What are the two aspects to eczema management?
Maintenance and management of flares
What is the key to maintenance of eczema?
Create an artificial barrier over the skin to compensate for the defective skin barrier
What is used as maintenance eczema treatment?
Emollients
How should emollients be used?
As thick and greasy as can be tolerates, used as often as possible. Used particularly after washing and before bed
What should patients with eczema avoid?
Activities that break down the skin barrier such as bathing in hot water, scratching or scrubbing their skin
Soaps that remove natural oils
What factors may trigger an eczema flare?
Changes in temperature Dietary products Washing powders Cleaning products Emotional events Stress
How can eczema flares be treated?
Thicker emollients
Topical steroids
Wet wraps
Treat complications
What may specialist treatment of severe eczema include?
Zinc bandages
Tacrolimus
Phototherapy
Systemic immunosuppressnats (corticosteroids, methotrexate)
What are some examples of some thin emollient creams?
E45
Dibprobase
Aveeno
Cetraben
What are some examples of thick, greasy emollitents?
50:50 ointment
Hydromol
Diprobase
Cetraben
What is the general rule for topical steroid treatment in eczema?
Use the weakest steroid for the shortest period required to get the skin under control
What are the side effects of using topical steroids?
Can lead to thinning of the skin which can make it more prone to flares, bruising, tearing, stretch marks and telangiectasia.
May be systemic absoprtion
What is the the steroid ladder?
Mild: Hydrocortisone
Moderate: Eumovate
Potent: Betnovate
Very potent: Dermovate
What is a common side effect of eczema?
Opportunistic bacterial infection of the skin
What is the most common organism that causes bacterial skin infection associated with eczema?
Staph. aureus
How is opportunistic skin bacterial infection treated?
Oral antibiotics (Flucloxacillin)
What is eczema herpeticum?
Viral skin infection in patients with eczema
What organisms cause eczema herpeticum?
Herpes simplex virus (HSV)
Varicella zoster virus (VZV)
What is the most common causative organism of eczema herpeticum?
HSV-1
In which patients does eczema herpeticum usually occur?
Those with a pre-existing skin condition (e.g. eczema or dermatitis) where the virus can easily enter the skin
How does eczema herpeticum present?
Widespread, painful, vesicular rash with systemic symptoms
What systemic symptoms may be found with eczema herpeticum?
Fever Lethargy Irritability Reduced oral intake Lymphadenopathy
What is the rash like in eczema herpeticum?
Widespread, erythematous, painful and sometimes itchy
Has vesicles that contain pus which may burst to leave small ulcers
How is a eczema herpeticum diagnosis confirmed?
Viral swabs of the vesicles
How is eczema herpeticum treated?
Aciclovir (oral or IV in severe cases)
What are the complications of eczema herpeticum?
Can be life threatening if not treated adequately
Bacterial superinfection can occur
What is psoriasis?
Chronic autoimmune condition that causes recurrent psoriatic skin lesions
What proportion of patients with psoriasis have a first degree relative with the condition?
1/3
What is the patches like in psoriasis?
Dry, flaky, scaly lesions that appear in raised rough plaques
Where is psoriasis commonly found on the body?
Extensor surfaces (elbows, knees and scalp)
What happens to the areas of psoriasis after a while?
There is abnormal buildup and thickening of the skin due to the rapid regeneration of new skin cells
What are the different types of psoriasis?
Plawue
Guttate
Pustular
Erythrodermic
What is plaque psoriasis?
Thickened erythematous plaques with silver scales found on extensor surfaces.
What is the most common type of psoriasis?
Plaque psoriasis
What is guttate psoriasis?
Small raised papules across trunk and limbs which may eventually turn into plaques
In which patients is guttate psoriasis most common?
Children
What may trigger guttate psoriasis?
Strep throat
Stress
Medication
What is pustular psoriasis?
Rare severe form of psoriasis where pustules form under areas of erythematous skin.
What is erythrofermic psoriasis?
Rare severe form with extensive erythematous inflamed areas covering most of the surface of the skin. The skin comes away in large patches
What are the specific signs suggestive of psoriasis?
Auspitz sign
Koebner phenomenon
Residual pigmentation
What is auspitz sign?
Small points of bleeding when plaques are scraped off
What is Koebner phenomenon?
Development of psoriatic lesions to areas of skin where trauma has occured
What are the different treatment options for psoriasis?
Topical steroids/ vitamin D analogues/ dithranol/ calcineurin inhibitors
Phototherapy
What conditions is psoriasis associated with?
Nail psoriasis
Psoriatic arthritis
Psychosocial implications
What is nail psoriasis?
Nail changes that occur with in patients with psoriases including pitting, thickening, discolouration, ridging and onycholysis
In what percentage of patients with psoriasis does psoriatic arthritis occur?
10-20%
What is the full name for acne?
Acne vulgaris
What is acne caused by?
Chronic inflammation in pockets within the skin (pilosebaceous unit)
What are pilosebaceous units?
Tiny units in the skin that contain hair follicles and sebaceous glands
What do sebaceous glands produce?
Natural skin oils and sebum
What is sebum?
A waxy substance produced by the sebaceous glands that coats, moisturises and protects the skin
What 3 things is acne the result of?
Increased production of sebum
Trapping of keratin
Blockage of the pilosebaceous unit
What increases the production of sebum?
Androgenic hormones
What are comedones?
Pores/ hair follicles that have become blocked
What bacteria plays a role in acne?
Propionibacterium acnes
What is Propionibacterium acnes?
A bacteria that colonises the skin
What are macules?
Flat marks on the skin
What are papules?
Small lumps on the skin
What are pustules?
Small lumps containing yellow pus
What are comedomes?
Skin coloured papules representing blocked pilosebaceous units
What are blackheads?
Open comedones with black pigmentation in the cntre
What are ice pick scars?
Small indentions in the skin that remain after acne lesions heal
What are hypertrophic scars?
Small lumps in the skin that remain after acne lesions heal
What are rolling scars?
Irregular wave-like irregularities of the skin that remain after acne lesions heal
What are the treatment aims with acne?
Reduce the symptoms
Reduce the risk of scarring
Minimise psychosocial impact
What is the stepwise treatment of acne?
- Topical benozyl peroxide
- Topical retinoids
- Topical antibiotics
- Oral antibiotics
- OCP
What is the last line option for acne and why are the last line?
Oral retinoids- highly teratogenic
Which COCP is the most effective for acne?
Dianette due to anti-androgen effects
What kind of medication is oral isotretinoin?
Retinoid
How do retinoids work?
Reduce production of sebum, reduce inflammation and bacterial growth
Why must careful consideration be taken when prescribing isotretinoin?
It is strongly teratogenic
What are the common side effects of isotretinoin?
Dry skin and lips
Photosensitivity
Depression/ anxiety
What is erythema nodosum?
Inflammation of the subcutaneous fat in the shins causing red lumps to appear
What is panniculitis?
Inflammation of fat
What is erythema nodosum caused by?
Hypersensitivity reaction
What are the potential causes of erythema nodosum?
Strep throat Gastroenteritis Mycoplasma pnaumoniae TB Pregnancy COCP NSAIDs Chronic disease
What chronic diseases may cause erythema nodosum?
IBD
Sarcoidosis
Lymphoma
Leukaemia
How does erythema nodosum present?
Red, inflamed, subcutaenous nodules across both shins which may be painful.
What investigations should be done when erythema nodosum is suspected?
Inflammatory markers Throat swab for strep CXR Stool microscopy & culture Faecal calprotectin
What is the management of erythema nodosum?
Investigate and treat underlying cause
Manage conservatively with rest & analgesia
Steroids in some causes
How long does erythema nodosum usually take to fully resolve?
Within 6 weeks
What is an exanthem?
Eruptive widespread rash
How many viral exanthemas are there?
6
What are the 6 red rashes?
Measles Scarlet fever Rubella Duke's disease Parvovirus B19 Roseola infantum
What is first disease?
Measles
What is second disease?
Scarlet fever
What is third disease?
Rubella
What is fourth disease?
Duke’s disease
What is fifth disease?
Parvovirus B19
What is sixth disease?
Roseola infantum
What causes measles?
Measles virus
Is measles contageous?
Highly
How is measles spread ?
Respiratory droplets
How soon after exposure to measles symptoms develop?
10-12 days later
What are the initial measles symptoms?
Fever
Coryzal symptoms
Conjunctivitis
What symptom confirms a diagnosis of measles?
Koplik spots
What are koplik spots?
Greyish white spots on the buccal mucosa
What is the buccal mucosa?
Lining of the cheeks and back of lips
How soon after the onset of symptoms fo koplik spots develop?
2 days later
Where does the measles rash usually start?
On the face/ behind the ears
How soon after the fever does the measles rash usually begin to develop?
3-5 days later
What type of rash is the measles rash?
Erythematous, macular rash with flat lesions
How long does measles usually last?
Self resolves after 7-10 days
How long should children with measles be isolated?
Until 4 days after their symptoms resolve
Who should be informed about all cases of measles?
Public health
What proportion of patients with measles develop a complication?
30%
What are the common complications of measles?
Pneumonia Diarrhoea Dehydration Encephalitis Meningitis Hearing loss Vision loss Death
What is the most common causative organism of scarlet fever?
Group A strep
What usually causes scarlet fever to develop?
Tonsillitis
What causes scarlet fever (pathophysiology)?
Exotoxin produced by strep pyogenes
What kind of rash develops with scarlet fever?
Red-pink, blotchy, macular rash with rough sandpaper skin
Where does the rash start in scarlet fever?
On trunk and spreads outwards
What other features may be present in scarlet fever?
Red, flushed cheeks Fever Lethargy Flushed face Sore throat Strawberry tongue Lymphadenopathy
How is scarlet fever treated?
Antibiotics for underlying streptococcal infection
What antibioitic is used for scarlet fever and for how long?
Penicillin V for 10 days
Who should be informed about all cases of scarlet fever?
Public health
What other conditions associated with group A strep infection may patients with scarlet fever also have?
Post-strep glomerulonephritis
Acute rheumatic fever
What is rubella caused by?
Rubella virus
How is rubella spread?
By respiratory droplets
How soon after exposure do symptoms of rubella start?
After 2 weeks
How does rubella present?
Mild erythematous macular rash
Where does the rubella rash start?
On the face
How long does the rubella rash usually last?
3 days
What symptoms may also occur with rubella?
Mild fever
Joint pain
Sore throat
Lymphadenopathy
How is rubella managed?
Supportive
Self limiting
Who needs to notified about all cases of rubella?
Public health
How long should children with rubella stay off school?
At least 5 days
What are the rare complications of rubella?
Thrombocytopenia
Encephalitis
Congenital rubella syndrome in pregnancy
What is congenital rubella syndrome?
Triad of deafness, blindness and congenital heart disease
What is Parvovirus B19 also known as?
Slapped cheek syndrome or erythema infectiosum
How does parvovirus B19 start?
Mild fever, coryza and non-specific viral symptoms
How long after symptoms begin do you get a rash with slapped cheek syndrome?
2-5 days
What is the rash like in Parvovirus B19?
Diffuse red rash on both cheeks
What kind of rash appears a few days after the slapped cheek rash?
Reticular erythematous rash affecting trunk and limbs. May be raised and itchy
Which patients are at risk of complications with parvovirus B19?
Immunocompromised
Pregnant women
Patients with haematological conditions
What are the complications of slapped cheek syndrome?
Aplastic anaemia
Encephalitis/ meningitis
Pregnancy complications
What is roseola infantum also known as?
Human herpesvirus 6
What is the typical pattern of illness with roseola?
Presents 1-2 weeks after infection with sudden, high fever that lasts 3-5 days. May also be coryzal symptoms. Rash appears for 1-2 days after fever.
What is the rash like in roseola infantum?
Mild erythematous macular rash across arms, legs, trunk and face
What is the main complication of roseola infantum?
Febrile convulsions
What is erythema multiforme?
Erythematous rash caused by hypersensitivity reaction
What are the most common causes of erythema multiforme?
Viral infections
Medications
How does erythema multiforme present?
Widespread, itchy, erythematous rash with characteristic target lesions
May be associated with other symptoms (e.g. stomatitis)
What are target lesions?
Red rings with larger red ring around (like bulls-eye target)
How is erythema multiforme diagnosis made?
Clinically based on rash
How is erythema multiforme managed?
Identify underlying cause
Usually resolves spontaneously
What is urticaria also known as?
Hives
What do hives look like?
Small, itchy lumps on skin
What other symptoms may be associated with urticaria?
Angioedema and flushing of skin
What are the typical causes of acute urticaria?
Allergies Contact with chemicals, latex or stinging lessons Medications Viral infections Insect bites Rubbing of skin
What is the pathophysiology of urticaria?
Release of histamine by mast cells
What causes acute urticaria?
Allergic reaction
What causes chronic urticaria?
Autoimmune reaction
What are the 3 subtypes of chronic urticaria?
Chronic idiopathic
Chronic inducible
Autoimmune
What is chronic idiopathic urticaria?
Recurrent episodes of chronic urticaria without clear underlying cause
What is chronic inducible urticaria?
Episodes of chronic urticaria that can be induced by certain triggers
What may trigger chronic inducible urticaria?
Sunlight Temperature change Exercise Strong emotions Hot or cold weather Pressure
What is autoimmune urticaria?
Chronic urticaria associated with an underlying autoimmune condition
How is urticaria managed
Antihistamines
What is the antihistamine of choice for urticaria?
Fexofenadine
What is chickenpox caused by?
VZV (Varicella zoster virus)
What is the characteristic chickenpox rash?
Widespread, erythematous, raised, vesicular lesions
What does a vesicular rash mean?
Fluid filled
Where does the chickenpox rash usually start and spread to?
Starts on trunk or face and spreads outwards to whole body.
What other symptoms may occur with chickenpox?
Fever
Itch
General fatigue/ malaise
How is chickenpox spread?
Direct contact with lesions or through infected droplets
How soon after exposure to chicken pox do patients become infected?
10 days to 3 weeks
What are the complications of chicken pox?
Bacterial superinfection Dehydration Conjunctival lesions Pneumonia Encephalitis Shingles
What can be given to unvaccinated pregnant women after exposure to chickenpox?
VZV immunoglobulins
What can chickenpox infection before 28 weeks gestation cause?
Congenital varicella syndrome: developmental problems in the fetus
What can chickenpox in the mother around time of delivery lead to?
LIfe threatening neonatal infection
How is chickenpox managed in otherwise healthy children?
Self-limiting
What medication can be used in immunocompromised patients with chickenpox?
Aciclovir
What causes hand foot and mouth disease?
Coxsackle A virus
How does hand foot and mouth disease usually start?
With URTI
What develops after 1-2 days in hand foot and mouth disease?
Small mouth ulcers
Blistering red spots across body
