15 - Dermatology Flashcards
What is eczema and the pathophysiology of this?
Chronic relapsing and remitting atopic condition caused by defects in the skin barrier allow entrance for allergens that create an immune response and inflammation
Eczema usually presents in under 5’s with dry, red, itchy and sore patches of skin over the flexor surfaces, and on the face and neck
What is the step ladder management for eczema?
Maintenance and Treatment of Flares
- Always avoid triggers
- First Line: Emollients at least twice daily
- Second Line: Topical steroids at lowest potency possible, Antibiotics, Sedating anti-histamine if itch affecting sleep
- Third Line: Topical calcineurin inhibitors (tacrolimus and pimecrolimus for steroid sparing)
- Fourth Line: Bandaging with emollients/zinc/steroids
- Firth Line: UV light therapy or oral ciclopsporin/methotrexate
What are some examples of emollients used in eczema and how do you instruct a parent to apply these?
- Apply 20 minutes before any steroids
- Must be doing minimum twice a day
Thin creams:
- E45
- Diprobase cream
- Oilatum cream
- Aveeno cream
Thick, greasy emollients:
- 50:50 ointment (50% liquid paraffin)
- Hydromol ointment
- Diprobase ointment
- Cetraben ointment
- Epaderm ointment
What is the steroid cream potency ladder and how do you instruct a parent to apply this?
Use finger tip units, 1 unit
What are signs of infected eczema?
- Weeping
- Pustules
- Crusts
- Rapidly worsening eczema
- Fever and malaise
Take swab if going to prescribe antibiotics, usually infected with S.Aureus
What antibiotics are used for infected eczema?
Topical Fusidic Acid or PO Flucloxacillin
How does eczema herpeticum present?
DUE TO HSV-1
- Widespread, painful, vesicular rash with systemic symptoms such as fever, lethargy, irritability and reduced oral intake
- Usually lymphadenopathy
- Punched out ulcers when pustules erupt
How is eczema herpeticum managed?
- Admission to hospital
- Viral swab before starting treatment
- IV aciclovir for at least 5 days, longer if not crusted over
- Refer to ophthalmology if eye involvement
- If bacterial superinfection give antibiotics
What is contact dermatitis and the types of this?
Type 4 hypersensitivity reaction following exposure to a causative agent. Presents with a dry, painful and pruritic skin rash.
- Irritant Contact Dermatitis: presents with a rash limited to the area of contact of the irritant
- Allergic Contact Dermatitis: sensitised to an allergen such as metals, rubber or plastics. Can extend beyond the site of direct contact.
Management
Management of Contact Dermatitis principally involves emollient creams and topical corticosteroids. Identification and avoidance of the irritant or allergen is required long term to prevent reoccurrence.
How can you investigate the cause of contact dermatitis?
Patch testing
A range of allergens are fixed on separate patches and placed on the skin. Two days later the patient returns and the patches are removed. After a further two days, the area is checked again and the reaction to each allergen is recorded
How is contact dermatitis managed?
- Avoid trigger e.g wear gloves at work
- Emollients
- Topical steroids
What is the atopic triad?
Approximately one third of children with eczema will develop asthma and/or hay fever in the future
What is psoriasis and some risk factors for this?
Chronic autoimmune condition that leads to patches of dry, flaky, scaly plaques over the extensor surfaces of elbows/knees and on the scalp
Due to rapid generation of new skin cells, resulting in an abnormal buildup and thickening of the skin in those areas
What are the different types of psoriasis?
- Plaque psoriasis
- Guttate psoriasis: small raised papules across the trunk and limbs. Over time can turn to plaques
- Pustular psoriasis: rare severe form of psoriasis where pustules form under areas of erythematous skin. Medical emergency and needs hospital admission
- Erythrodermic psoriasis: medical emergency and patients require admission
What is the most common type of psoriasis in children and how does it present?
Guttate
- Small red plaques distributed across the torso
- Described as having a ‘raindrop’ appearance on the skin
- Often seen following strep infection
What are 3 signs suggestive of psoriasis?
- Auspitz sign refers to small points of bleeding when plaques are scraped off
- Koebner phenomenon development of psoriatic lesions to areas of skin affected by trauma
- Residual pigmentation of the skin after the lesions resolve
What are some differentials for psoriasis in children?
- Juvenile psoriatic arthropathy
- Eczema
- Pityriasis rosea
- Lichen plans
How is psoriasis managed?
- Regular emollients
First-line
- Potent corticosteroid once daily plus vitamin D analogue once daily, one in the morning and the other in the evening
- If no improvement after 8 weeks then offer Vit D analogue twice daily
- If no improvement after 8-12 weeks then offer either: coal tar or short-acting dithranol
Second Line
- Narrowband UVB 3 times a week
- Psoralen + ultraviolet A light (PUVA)
Systemic therapy
- Oral methotrexate is used first-line
- Ciclosporin
- Biological agents: infliximab, etanercept and adalimumab
How old do you have to be for PUVA therapy for psoriasis?
Over 10
What are some co-morbidities with psoriasis?
Nail psoriasis: pitting, thickening, discolouration, ridging and onycholysis
Psoriatic arthritis occurs in 10 – 20% of patients with psoriasis and usually occurs within 10 years of developing the skin changes. It typically affects people in middle age but can occur at any age.
Depression and anxiety
Cardiovascular Disease: obesity, hyperlipidaemia, hypertension and type 2 diabetes.
What is the pathophysiology of acne?
Chronic inflammation, with or without localised infection of the pilosebaceous unit.
Increased production of sebum, trapping of keratin and blockage of the pilosebaceous unit
Androgenic hormones increase the production of sebum, which is why acne is exacerbated by puberty
Propionibacterium acnes bacteria
How is the severity of acne classified?
- Mild: open and closed comedones with or without sparse inflammatory lesions
- Moderate: widespread non-inflammatory lesions and numerous papules and pustules
- Severe: extensive inflammatory lesions, which may include nodules, pitting, and scarring
How is acne managed in children?
Always consider psychosocial impact and screen for anxiety and depression
- Topical retinoid or Topical benzoyl peroxide
- Topical combination therapy (topical antibiotic like clindamycin, benzoyl peroxide, topical retinoid)
- Oral antibiotics: tetracyclines for 3/12 like lymecycline, oxytetracycline, doxycycline. Avoid younger than 12 years of age
- COCP: alternative to antibiotics, can use Dianette but only for 3/12 as risk of VTE
- Oral Isotretinoin: only under specialist supervision
How does oral isotretinoin (Roaccutane) work and what are some of the side effects?
It is a retinoid, (Vitamin A analogue) and works by reducing production of sebum, reducing inflammation and reducing bacterial growth. It can only be prescribed under expert supervision by a dermatologist. It is strongly teratogenic (harmful to the fetus during pregnancy). Patients need to have effective and reliable contraception and must stop isotretinoin for at least a month before becoming pregnant.
Side effects
- Highly teratogenic: need effective contraception and must stop at least a month before pregnancy
- Dry skin and lips
- Photosensitivity of the skin to sunlight
- Depression, anxiety, aggression and suicidal ideation: screen prior to treatment
- SJS and TEN
What is molluscum contagiousum and how does it present?
Small, flesh coloured papules with a central, umbilication that appear in clusters.
Poxvirus
Passed on by sharing towels and bed sheets.
How should molluscum contagiousum be managed?
- Reassure self-limiting but can take up to 18 months. Scratching or picking the lesions should be avoided as can scar or spread
- Avoid sharing towels or other close contact
- If bacterial superinfection infection give topical fuscidic acid or oral flucloxacillin.
- If Immunocompromised or in problematic areas such as the eyelid or anogenital area consider cryotherapy or topical potassium hydroxide, podophyllotoxin, imiquimod or tretinoin
How does pityriasis rosea present and what is it caused by?
Human herpes virus (HHV-6 or HHV-7)
- Prodrome of headache, loss of appetite and flu-like symptoms.
- Herald patch: faint red or pink, scaly, oval shaped lesion that is 2cm or more in diameter, usually occurring somewhere on the torso. It appears 2 or more days prior to the rest of the rash
- Faint red or pink, slightly scaly, oval shaped lesions in christmas tree pattern
What is seborrhoeic dermatitis?
Inflammatory skin condition that affects the sebaceous glands
It affects areas that have a lot of these glands, such as the scalp,nasolabial foldsandeyebrows.
Erythema, dermatitis and crusted dry skin. Malassezia yeast colonisation has a role to play
How does seborrhoeic dermatitis present in younger children and how is it managed?
Cradle Cap
Crusted flaky scalp. It is self limiting and usually resolves by 4 months but can last until 12 months
First line: apply baby or olive oil and gently brush the scalp then wash off. White petroleum jelly can be used overnight to soften crusted areas before washing off in the morning
Second Line: clotrimazole or miconazole, used for up to 4 weeks
What is nappy rash and some risk factors for this?
Contact dermatitis in the nappy area caused by friction between the skin and nappy and contact with urine and faeces in a dirty nappy
Breakdown in skin and the warm moist environment in the nappy can lead to added infection with candida or bacteria
How is nappy rash managed?
- Switch to highly absorbent nappies
- Change nappy and clean skin as soon as possible after wetting or soiling
- Use water or gentle alcohol free products for cleaning the nappy area
- Ensure nappy area is dry before replacing the nappy
- Maximise time not wearing a nappy
Infection with candida or bacteria: anti-fungal cream (clotrimazole or miconazole) or antibiotic (fusidic acid cream or oral flucloxacillin)
What is a non-blanching rash caused by and what is the most important differential to consider with this?
Meningococcal Septicaemia
Bleeding under the skin
Petechiae are small (< 3mm), non blanching, red spots on the skin caused by burst capillaries
Purpura are larger (3 – 10mm) non-blanching, red-purple, macules or papules created by leaking of blood from vessels under the skin.
What are some differentials for a non-blanching rash?
- Meningococcal septicaemia or other bacterial sepsis
- Henoch-Schonlein purpura (HSP): purpuric rash on legs and buttocks and may have associated abdominal or joint pain
- Idiopathic thrombocytopenic purpura (ITP): This develops over several days in an otherwise well child
- Acute leukaemias
- Haemolytic uraemic syndrome (HUS): oliguria and signs of anaemia
- Mechanical: Strong coughing, vomiting or breath holding can produce petechiae above the neck and around the eyes.
- Traumatic: Tight pressure on the skin, for example in non-accidental injury
- Viral illness: usually influenza and enterovirus
What is impetigo?
Superficial bacterial skin infection, usually caused by the staphylococcus aureus bacteria. A “golden crust” is characteristic of a staphylococcus skin infection. Less commonly caused by the streptococcus pyogenes bacteria
Contagious and children should be kept off school during the infection
Occurs when bacteria enter via a break in the skin
Non-bullous or bullous
What is non-bulbous impetigo and how is it treated?
Presentation
- Occurs around the nose or mouth
- The exudate from the lesions dries to form a “golden crust”
Management
- Hygiene advice
- Hydrogen Peroxide 1% for 5 days
- If above doesn’t work give topical Fusidic acid
- Oral flucloxacillin more wide spread or severe impetigo
What is bullous impetigo?
- Caused by staph aureus bacteria that produce epidermolytic toxins that break down the proteins that hold skin cells together. This causes 1 – 2 cm fluid filled vesicles to form on the skin
- Heal with no scarring
- More common in neonates and children under 2 years
- Common for patients to have systemic symptoms e.g fever
- In severe infections when the lesions are widespread, it is called staphylococcus scalded skin syndrome
What is staphylococcal scalded skin syndrome?
Caused by a type of staphylococcus aureus bacteria that produces epidermolytic toxins that are protease enzymes that break down the proteins that hold skin cells together
Usually affects children under 5’s as older children and adults have developed immunity to the epidermolytic toxins
How does staphylococcal scalded skin syndrome present?
- Generalised patches of erythema
- Then fluid filled bullae, which burst and leave very sore, erythematous skin below
- Nikolsky sign positive: gentle rubbing of the skin causes it to peel away
- Systemic symptoms of fever, irritability, lethargy and dehydration. If untreated it can lead to sepsis and potentially death.
How is SSSS managed?
- Admission
- IV antibiotics
- Emollients
- Fluid and electrolyte balance as risk of dehydration
If treated promptly child will make full recovery with no scarring
What other condition apart from SSSS has a positive Nikolsky sign?
TEN (toxic epidermal necrolysis)
SJS is more common in children than TEN. How does this present?
- Start with non-specific symptoms of fever, cough, sore throat, sore mouth, sore eyes and itchy skin
- Then develop purple red rash that blisters
- A few days after the blistering starts, the skin starts to break away and shed leaving the raw tissue underneath
- Pain, erythema, blistering and shedding can also happen to the lips and mucous membranes
What is the difference between SJS and TEN?
Both have mucus membrane involvement
SJS <10% body surface area
TEN >30% body surface area
What are some causative agents of SJS?
Usually about a week after starting drug, STOP DRUG IMMEDIATELY WHEN THIS DEVELOPS
How may HPV present in children?
- Condyloma acuminatum
- Verrucae
- Papillomas
- Condylomas
- Focal epithelial hyperplasia (image)
What is a cutaneous wart?
- Small, rough growths caused by infection of keratinocytes with HPV. They can appear anywhere on the skin but are commonly seen on the hands and feet
- A verruca is a wart on the sole of the foot
What are the different types of cutaneous warts?
- Common: firm and raised with a rough surface that resembles a cauliflower (common on knuckles, knees, and fingers)
- Periungual: around the nails, can be painful and disturb nail growth
- Plane: round, flat-topped, and skin coloured or greyish yellow
- Filiform: finger-like appearance and may have a stalk
- Palmar and plantar: central dark dots and may be painful
- Mosaic: palmar or plantar warts coalesce into larger plaques on the hands and feet
How are warts treated?
- Most self resolve within 2 years, older children may take 5-10 years
- Only treat if painful, unsightly, persisting or requested
- Cryotherapy or Topical Salicyclic Acid for up to 12 weeks
What are some causes of fever and a maculopapular rash in children?
What are some causes of fever and a vesicular/pustular/bullous rash in a child?
What are some causes of fever and a petechial/purpuric rash in children?
Match the following
