Dermatology Flashcards
What is the cause of acne vulgaris?
Chronic inflammation
With or without localised infection
Increased production of sebum, trapping of keratin
What is the management of acne?
Topical benzoyl peroxide to reduce inflammation Topical retinoids slows sebum Topical antibiotics e.g. clindamycin Oral antibiotics e.g. lymecycline Oral contraception
What is the risk of oral retinoids?
Careful follow up
Need reliable contraception
Highly teratogenic
What is roaccutane?
Oral isotretinoin - retinoid
Reduces production of sebum, inflammation
What are some of the side effects of roaccutane?
Dry skin and lips
Photosensitivity
Depression, anxiety, aggression, suicidal ideation
Rare - Stevens-Johnson, toxic epidermal necrolysis
Highly teratogenic, stop one month before becoming pregnant
What is eczema?
Chronic atopic condition
Defects in skin barrier
Inflammation of the skin
What is the presentation of eczema?
Infancy
Dry red itchy sore patches
Over flexor surfaces - inside of elbows, knees
What is key to the maintenance of eczema?
Create artificial barrier over skin to compensate Use of emollients Do not scratch and scrub Use of soap substitutes Avoid triggers, enviromental, stress
What is the management of flares?
Thicker emollients Topical steroids Wet wraps Treat infections IV antibiotics, oral steroids
Zinc impregnated bandages
Topical tacrolimus
Phototherapy
Immunosuppressants - corticosteroids, methotrexate, azathioprine
What are some examples of some emollients that can be used for eczema?
Thin creams:
E45, diprobase, oilatum, Aveeno, cetraben
Thick:
50:50 liquid paraffin
Hydromol, diprobase ointment
What is the steroid ladder for eczema?
Mild - hydrocortisone
Moderate - eumovate
Potent - betnovate
Very potent - dermovate
What is a common cause of bacterial infection in eczema?
Staphylococcus aureus
Treatment with flucloxacillin
May need admission, IV antibiotics
What is eczema herpeticum?
Viral skin infection due to herpes simplex virus or varicella zoster virus
Usually occurs in patient with pre-existing skin condition e.g. eczema or dermatitis
What is the presentation of eczema herpeticum?
Widespread painful vesicular rash - vesicles containing pus, sometimes itchy
Fever, lethargy, irritability
Reduced oral intake
Lymphadenopathy
What is the management of eczema herpeticum?
Viral swabs
Aciclovir - oral or IV
What is the cause of bullies impetigo?
Staph aureus infection
Blistering rash
Treated with systemic antibiotics e.g. penicillinase resistant penicillin
What are the causes of napkin rashes?
Common Contact dermatitis Infantile seborrhoeic dermatitis Candida infection Atopic eczema
Rare
Langerhans histiocytosis
Wiskott-Aldrich syndrome
What occurs in a nappy rash?
Irritant dermatitis if nappies not changed enough or diarrhoea
Irritant effect of urine
Affects buttocks, perineal region, lower abdomen and top of thighs. Flexures spared.
Use of emollients or mild corticosteroids.
Candida can cause rash, use topical anti fungal agent
What is infantile seborrhoeic dermatitis?
Cradle cap
Crusted flaky scalp
Self limiting condition - 4 months-12 months
What is the treatment for cradle cap?
Baby oil, brush scalp
White petroleum jelly
Anti-fungals next step for up to 4 weeks - clotrimazole or miconazole
What is seborrhoeic dermatitis of the scalp?
Dandruff or oily scale brown crusting
More common in adults and adolescents
Use ketoconazole shampoo
Topical steroids if severe itching
What occurs in seborrhoeic dermatitis of the face and body?
Red flaky crusted itchy skin
Affects eyelids, nasolabial folds, ears, chest, back.
Treat with clotrimazole or miconazole antifungals
Up to 4 weeks
What are some itchy rashes?
Atopic eczema Chickenpox Urticaria/allergic reactions Contact dermatitis Insect bites/papular urticaria Scabies Fungal infections Pityriasis rosea
What are causes of exacerbation of eczema?
Bacterial infection Viral infection Ingestion of allergen e.g. egg Contact with irritant Environment Change in medication Psychological stress
When are skin rashes examples of systemic disease?
SLE or dermatomyositis facial rash Purpura over buttocks, lower limbs, elbows - HSP Erythema nodosum and erythema multiforme Stevens-Johnson Urticaria
What occurs in Steven-Johnsons?
Bullous form of erythema multiforme
Involves mucous membranes
Eye involvement - conjunctivitis, corneal ulceration, uveitis
What are causes of erythema nodosum?
Streptococcal infection Primary tuberculosis IBD Drug reaction Idiopathic Sarcoidosis - common association in adults, rare in children
Tender nodules over legs
Fever and arthralgia
What are the causes of erythema multiforme?
Herpes simplex
Mycoplasma pneumoniae
Drug reaction
Idiopathic
What is psoriasis?
Chronic autoimmune condition causes psoriatic skin lesions
What are the types of psoriasis?
Plaque psoriasis - thickened erythematous plaques with silver scales on extensor surfaces and scalp
Guttate psoriasis - common in children, small raised papule across trunk/limbs
Often triggered by strep throat infection
Pustular psoriasis - pustules under erythematous skin, med emergency
Erythrodermis psoriasis
What is the presentation of psoriasis?
Guttate more common, triggered by throat infection
Plaques of psoriasis smaller, softer, less prominent.
What is Auspitz sign?
Bleeding when plaques scraped off
What is Koebner phenomenon?
Development of psoriatic lesions on skin affected by trauma
What is residual pigmentation?
Pigmentation of the skin after the lesions resolve
What is the management of psoriasis?
Topical steroids Topical vit D analogues - calcipotriol Topical dithranol Topical calcineurin inhibitors e.g. tacrolimus Phototherapy
Dovobet, Enstilar
What are common signs and associations with psoriasis?
Nail psoriasis - nail pitting, thickening, discolouration, ridging, onycholysis
Psoriatic arthritis
Psychosocial implications, increased risk of CVD, obesity, hyperlipidaemia, HTN, type 2 diabetes
What are the viral exanthems?
First disease: Measles Second disease: Scarlet Fever Third disease: Rubella (AKA German Measles) Fourth disease: Dukes’ Disease Fifth disease: Parvovirus B19 Sixth disease: Roseola Infantum
What are the features of the measles rash?
Koplik spots on muccosa
Rash on face, behind ears, 3-5 days after fever, macular
Fever, coryza, conjunctivitis
What are the complications of measles?
Pneumonia Diarrhoea Dehydration Encephalitis Meningitis Hearing loss Vision loss Death
What are the features of Scarlet fever?
Group A strep - tonsillitis, due to the endotoxin
Red-pink macular rash Sandpaper skin Fever Lethargy Flushed face Sore throat Strawberry tongue Cervical lymphadenopathy
What is the treatment for scarlet fever?
Phenoxymethylpenicillin 10 days
No school until 24 hours after starting antibiotics
What is the Rubella rash?
Milder erythematous macular rash, starts on face, spreads to rest of body
Cervical lymphadenopathy
What are the complications of parvovirus B19?
Aplastic anaemia
Encephalitis or meningitis
Pregnancy complications including fetal death
Rarely hepatitis, myocarditis or nephritis
Who is at risk of complications with slapped cheek syndrome/B19?
immunocompromised patients
pregnant women
patients with haematological conditions such as sickle cell anaemia, thalassaemia, hereditary spherocytosis and haemolytic anaemia
What are causes of acute urticaria?
Stimulation of release of mast cells and histamine
Allergies to food, medications or animals
Contact with chemicals, latex, stinging nettles
Medications
Viral infections
Insect bites
Dermatographism - rubbing of the skin
What are causes of chronic urticaria?
Autoimmune condition
Autoantibodies target mast cells, release histamines
Chronic idiopathic
Chronic inducible: sunlight, temp, exercise, strong emotions, hot or cold weather, pressure
Autoimmune chronic urticaria is associated with an underlying autoimmune condition e.g. SLE
What is the management of urticaria?
Antihistamines
Fexofenadine
Oral steroids
Anti-leukotrienes e.g. montelukast
Omalizumab - targets IgE
Cyclosporin
What are the features of chickenpox?
Widespread erythema Raised vascular blisters Trunk or face Spreads outwards affecting whole body Fever, itching, malaise
What are the complications of chickenpox?
Bacterial superinfection Dehydration Conjunctival lesions Pneumonia Encephalitis (presenting as ataxia)
What is the management of chickenpox?
Mild self limiting
Aciclovir if immunocompromised, neonates, those at risk of infection
Calamine or chlorphenamine for itching
What is molluscum contagiosum?
Small flesh coloured papules, central dimple
Due to viral poxvirus
Crops of lesions
Spread through contact or sharing items
Resolves without treatment
Specialist treatment for those with extensive lesions or immunocompromised e.g.
topical potassium hydroxide, benzoyl peroxide, surgical removal or cryotherapy
What is tinea capitis?
Ringworm of the scalp
Well demarcated hair loss
Itching, dryness, erythema of scalp
More common in kids
What is tinea pedis?
Ringworm of feet
Athletes foot
White/red
Flaky cracked itchy patches
Between the toes
Skin may split and bleed
What is tinea cruris?
Ringworm of the groin
What is tinea corporis?
Ringworm on the body
What is onchyomycosis?
Fungal nail infection
Thickened discoloured deformed nails
What is the presentation of ringworm rash?
Itchy rash
Erythematous scaly
Well demarcated
Check toenails in presenting with ringworm, may be because fungal nail infection has spread to the skin
What is the management of ringworm?
Microscopy and culture of scrapings from scales
Anti-fungals
Creams - clotrimazole
Shampoo - ketoconazole for tinea capitis
Oral antifungals e.g. fluconazole
Nail lacquer for 6-12 months
Mild topical steroid to settle inflammation
Wear loose breathable clothing, keep clean and dry, avoid sharing towels etc
Avoid scratching
What is tinea incognito?
Fungal skin infection results from use of steroids to treat initial fungal infection
Steroid improves inflammation but dampens immune response
What is scabies?
Tiny mites burrow under skin, causes infection
Lay eggs in skin, can take up to 8 weeks for symptoms
Track marks where burrow
Rash in finger webs
What is the management of scabies?
Permethrin cream applied to whole body when cool
Left on for 8-12 hours
Repeat 1 week later to kill all eggs
Treat whole household
Oral ivermectin single dose after 1 week if difficult to treat/crusted scabies (immunocompromised patients)
What is the management of headlice?
Dimeticone lotion, fine combs, detection combing
What are the differentials for non blanching rashes?
Meningococcal sepsis Other bacterial sepsis Henoch Schonlein Purpura Idiopathic thrombocytopenia purpura Acute leukaemia Haemolytic uraemia syndrome Mechanical - strong coughing, vomiting or breath holding causes superior vena cava distribution Traumatic - NAI Viral illness
What are key investigations in a non blanching rash?
Full blood count: Anaemia can suggest HUS or leukaemia. Low white cells can suggest neutropenic sepsis or leukaemia. Low platelets can suggest ITP or HUS.
Urea and electrolytes: High urea and creatinine can indicate HUS or HSP with renal involvement.
C-reactive protein (CRP): This is a non-specific indication of inflammation or infection and can be useful but not definitive in excluding sepsis.
Erythrocyte sedimentation rate (ESR): This is a non-specific indication of inflammatory illness such as a vasculitis (HSP) or infection.
Coagulation screen, including PT, APTT, INR and fibrinogen can diagnose clotting abnormalities.
Blood culture: This can be useful but not definitive in diagnosing or excluding sepsis.
Meningococcal PCR: This can confirm meningococcal disease, although this should not delay treatment.
Lumbar puncture: To diagnose meningitis or encephalitis.
Blood pressure: Hypertension can occur in HSP and HUS. Hypotension can occur in septic shock.
Urine dipstick: Proteinuria and haematuria can suggest HSP with renal involvement, or HUS.
What is impetigo?
Superficial bacterial skin infection Staph aureus Golden crust - staph infection Contagious Due to break in skin Bullous or non bullous
What is non-bullous impetigo?
Occurs around nose/mouth
Exudate from lesions dries - golden crust
Treatment with topical fusidic acid, oral flucloxacillin if wide spread/more severe
What is bullous impetigo?
Always due to staph aureus
Toxins create vesicles
Then burst - crust
Lesions painful and itchy
More common in neonates and children under 2
Feverish and unwell
Swabs and treatment with flucloxacillin
What is staphylococcus scalded skin syndrome?
Severe bullous impetigo infection leads to widespread lesions
Generalised patches of erythema on skin
Skin thin and wrinkled
Bullae burst, leaves sore burnt looking skin
Nikolsky sign - gentle rubbing of skin can cause it to peel away
IV antibiotics and fluids
What are the complications of impetigo?
Cellulitis if the infection gets deeper in the skin Sepsis Scarring Post streptococcal glomerulonephritis Staphylococcus scalded skin syndrome Scarlet fever
What are modes of HPV transmission in children?
Non sexual, directly
Maternal transmission?
Sexual abuse - anogenital warts ?safeguarding
What are the clinical manifestations of HPV infection?
Oral HPV infections
Juvenile onset laryngeal papillomas
Anogenital warts
What strains of HPV cause cervical cancer?
HPV 16 and HPV 18
What strains of HPV cause genital warts and laryngeal papillomatosis?
HPV 6 and HPV 11
What are risk factors for persistent genital HPV infections?
Early age first sexual intercourse
Multiple partners
Smoking
Immunosuppression
