Dermatology Flashcards
Why do hives occur ?
Due to the release of histamine from mast cells due to exposure to an allergen or idiopathically
What are the clinical features of urticaria (Hives) ?
- Small itchy bumps
- Can be acute or chronic
- Can be specific or widespread
- Skin may be flushed or erythematous
What are some causes of acute urticaria ?
- Allergies
- Contact with allergen
- Medications
- Infection or insect bites
What are some causes of chronic urticaria ?
Chronic idiopathic – Recurrent episodes without a clear cause
Chronic inducable – Sunlight, temp exposure, emotions, pressure, weather
Autoimmune – Associated with an underlying condition like SLE.
What is the main treatment for urticaria ?
Antihistamines
Oral steroids can be given in severe cases
What is the first line of treatment for chronic urticaria ?
Fexofenadine
What is nectrotising fasciitis ?
Infection involving the deep soft tissue compartments. Organisms migrate from subcutaneous tissue along the fascial planes
What are the main causative organisms of NF ?
Group A strep
Gram neg organisms acquired from seawater
Fungal infection like candida
Many cases are polymicrobial (AEROBIC AND ANAEROBIC)
What are some of the clinical features of NF ?
Pain out of proportion to clinical findings
Skin discoloration and skin blistering
Fever and malaise
Fever and hypotension
Tachycardia
Local pain, swelling and erythema
Poor margins and pain extending beyond the margins
Crepitus in palpation
Offensive discharge
Oedema
Bullae (blisters)
What are some of the Rf for NF ?
Skin injury
Impaired immunity like malignancy, immunosuppression, diabetes, CKD ect
IV drug use
On investigation, what will present in NF ?
Raised WCC unless immunocompromised
Hyponatremia
Raised CRP and CK
Raised lactate
BC, wound swabs and debrided tissue gram stain and culture
Coag screen and group and save
A CT can be useful but should not delay treatment
What is the bedside finger test for nectrotising fascitis ?
Small incision is made to the fascia under LA
Tissue is probed with sterile glove finger
Absence of bleeding, purulent pus and lack of tissue resistance
How is NF medically managed ?
- A-E assessment
- BS antibiotics as soon as possible
How is NF surgically managed ?
Urgent surgical debridement and wound monitor. May need further surgery until the infection is controlled.
What is cellulitis ?
Infection of the skin and the soft tissues underneath. Patients often have a breach in the skin barrier like trauma, eczema, fungal nail infections or ulcers
Most common causative organisms of cellulitis ?
Staphylococcus aureus
Group A strep (Pyrogens)
Group C step (dysgalactiae)
MRSA
What are the clinical features of cellulitis ?
Erythema
Warm or hot to touch
Tense and thickened
Odema
Bullae
What infective organism does a yellow crust indicate ?
staphylococcus aureus
What classification is used to classify cellulitis ?
THE ERON classification is used to classify cellulitis
Class 1 – no systemic toxicity or comorbidity
Class 2 – systemic toxicity or comorbidity
Class 3 – significant systemic toxicity or significant comorbidity
Class 4 – sepsis or life-threatening
What is first line of treatment for cellulitis ?
Flucloxacillin is first line in cellulitis and can be given oral or IV (IV in class ¾ or co-morbidities)
What are some of the other antibiotic options available to treat cellulitis ?
Clarithromycin, clindamycin and Co-amoxiclav can also be used.
What medications can trigger psoriasis ?
BB, Antimalarials, Lithium and NSAIDS
What are some of the other triggers for psoriasis ?
Positive family history in 1/3 of patients
Can be triggered by – Stress, trauma, infection (Strep and HIV), alcohol, smoking, weather
Withdrawal of steroids.
What are the clinical features of psoriasis ?
Dry, flaky, scaly skin
Erythematous lesions in raised and rough plaques
Extensor surfaces like the elbows, Knees and scalp.
Symmetrical distribution.
What are the nail changes associated with Psoriasis ?
Nail pitting
Onycholysis (Separation of nail plate from nail bed)
Subungual hyperkeratosis (Thickening of the nailbed)
What signs are associated with psoriasis ( Not on the nailbed)?
Auspitz sign – Small points of bleeding when plaques are scraped off
Koebner phenomenon – Psoriatic lesions to areas of skin affected by trauma.
Residual pigmentation of the skin after lesions evolve.
Describe plaque psoriasis ?
Thick erythematous plaques with sliver scales, common on the extensor surfaces and scalp. Most common in adults
What is guttate psoriasis ?
Most commonly occurs in children. Small raised papules across the trunk and the limbs. These can be erythematous and scaly and can transform into plaque psoriasis. Often triggered by a streptococcal throat infections/stress/medication. Spontaneously resolves within 3-4 months.
What is a common infective cause of guttae psoriasis ?
Streptococcus throat infection
What is pustular psoriasis ?
– Rare and severe. Pustules form under areas of erythematous skin. Patients are systemically unwell and a medical emergency. Should be admitted to hospital.
What should all patients with psoriasis do in terms of management ?
All patients should manage RF and use emollient to reduce scale and itch
What are the topical treatments for psoriasis (from first line to final line)?
Corticosteroids target inflammation and vitamin D analogues reduce keratinocyte proliferation
1- Potent topical corticosteroid OD (Betnovate) + topical vitamin D OD (eg Dovonex/Calcipotriol) applied at different times
2 – Stop corticosteroid and use topical Vit D TD
3 - Stop the topical vitamin D, apply potent topical corticosteroid twice daily
Dithranol + tar are alternatives
What phototherapy is offered in psoriasis ?
Narrow band UVB
What are some systemic treatments of psoriasis ?
methotrexate ( Can cause panty cytopenia, hepatoxicity and pneumonitis), then ciclosporin ( 5 Hs), then acitretin ( Tetarogenic)
What are the side effects of methotrexate ?
Pulmonary and liver fibrosis
Myelosupression
Mucositis
Tetarogenic
What are the side effects of ciclosporin (Immunosuppressant - It is used to prevent rejection of new organs following a transplant operation, rheumatoid arthritis, severe dermatitis and psoriasis or nephrotic syndrome)
5 HS
What is a key risk of acitretin (used in severe psoriasis) ?
Used in severe psoriasis - Teratogenic
Can biologics like infliciumab be used in psoriasis ?
Yes
What is an important side effect of biologics ?
Can cause activation of latent TB
What is the pathophysiology of acne vulgaris ?
Disorder of the pilosebaceous follicles causing comedones, papules and pustules to form.
What is the typical presentation of acne ?
Often effects during puberty and adolescence
Typical distribution across the face, upper chest and upper back
Typical inflamed and sore spots on the skin.
What is the first line of treatment of acne vulgaris ?
- Topical retinoid with or without benzoyl peroxide or a topical antibiotic (Like clindamycin)
If 1st line topical antibiotic treatments are ineffective, what is the next line of treatment for acne vulgaris ?
Oral Lymecycline/doxycycline. Note this should not be used in pregnancy or breastfeeding.
What is the last line of treatment for acne vulgaris ?
Oral retinoids (isotretinoin/Roaccutane ) - Effective last line option. HIGHLY TERATOGENIC. Hence patients need to be on effective contraception. Must be off the medication for over a month before conceiving.
What are the side effects of roaccutane ?
Side effects
Dry skin and lips
Photosensitivity
Depression, anxiety screening
SJS – TEN
Teratogenic
What is the most effective combined contraceptive pill for acne ?
- Co-cyprinoid (Increased risk of thromboembolism) so it is not prescribed long term.
What is actinic keratosis ?
Pre-cancerous scaly spot found on sun damaged skin. Also known as solar keratosis.
Can be an early form of cutaneous SCC.
Often is found on sun exposed sites
Bald heads
What is actinic keratosis a precursor of ?
SCC
What are the clinical features of actinic keratosis ?
Flat or thickened papule/plaque
White/yellow, scaly warty surface
Can be tender or asymptomatic
Skin colored/red/pigmented
Commonly found on the hands and face, ears, temples and forehead. Also on balding scalp.
Can be itchy
Hyperpigmentation
What are the risk factors for actinic keratosis ?
Prolonged sun exposure
Fair skin with a history of sunburn
Immunosuppression (Methotrexate)
Other signs of photoaging skin.
A tender, thickened, ulcerated or enlarging actinic keratosis is suspicious evolution to SCC.
How is actinic keratosis diagnosed ?
Usually diagnosed clinically or by dermosocopy.
Biopsy is used if the lesion is not responding to treatment and to exclude an SCC.
How are large areas of actinic keratosis managed ?
Larger areas – 5 – fluorouracil, NSAIDS or imiquimod
How are localized lesions of actinic keratosis removed ?
Cryotherapy using liquid nitrogen
Shave, curettage and electrocautery
Excision
What is important to inform patients after the removal of actinic keratosis ?
Sun protection advice
What is Bowens disease ?
SCC in situ. Presents as a scaly, thickened macule or patch and often asymptomatic. Very common in the lower legs in women and there may be multiple patches.
VERY EARLY FORM OF SKIN CANCER
How is bowens disease treated ?
The same as actinic keratosis
What bacteria is responsible for SSSS ?
S Aureus
What are the features of SSSS ?
- Sparing of the oral mucosa
- Usually evidence of Graze or pre existing injury
- Prevalent in children
- Bullous, sore lesions that can bust
- Fever, lymphadenopathy ect
What are the features of lichen planus ?
- Lacy white oral mucosa
- Rash on the neck, flexor aspects of the arms and wrists
- Symmetrical distribution.
What risk factors is lichen planus thought to be associated with ?
- Anxiety
- Stress
- Viral infection
- Drug reactions
What is the first line of treatment for cellulitis in patients with a penicillin allergy ?
Clarithromycin
What causes erythema multiforme ?
Hypersensitivity reaction
What infection is erythema multiforme commonly associated with ?
HSV (coldsores) and mycoplasma pneumonia.
How does erythema multiforme commonly present ?
- Widespread, itchy, erythematous rash.
- Characteristic target lesions
- Can cause a sore mouth
- Symptoms come on abruptly over a few days and may be associated with ….
- Mild fever, stomatitis, muscle and joint aches, headaches and flu like symptoms.
How is erythema multiforme managed ?
- Diagnosis - Clinically on the appearance of the rash
- Obvious cause - Penicillin use or coldsore, can be managed Conservative.
- No clear cause - may need a CXR to rule out mycoplasma pneumoniae.
- Severe cases may need admission to hospital if it affects the oral mucosa and IV fluids, analgesia, steroids ecr.
Are BBCs reffered on suspected cancer pathway ?
No due to the slow growing nature of the lesion. Usually only referred if there are any concerning features.
A newborn baby boy is being examined by his paediatrician. His examination is unremarkable except for a 1x1cm dark brown oval-shaped lesion on his left forearm. It is flat and has a regular border. Which of the following is the most appropriate action to take based on the most likely diagnosis ?
Most likely a benign naevus. Reassure the parents
Pyroderma gangrnosum is a complication of IBD. How is it managed ?
Topical steroids (in smaller ones) larger may need management surgically
What is leukoplakia ?
Pre-malignant condition that presents as white, hard spots on the mucous membranes of the mouth.
Leukoplakia can present similarly to candidiasis and lichen planus, how can it be differentiated ?
Candadiasis and lichen planus the lesions can be rubber off.
When is the next step in a patient who has leukoplania ?
Biopsy refferal to exclude SCC and regular follow up to exclude malignant transformation to SCC.
What factors can exacerbate psoriasis ?
Trauma
Alcohol
Drugs - BB, lithium, antmalarials (quine), NSAIDS and ACE inhib as well as infliximab
Withdrawal of systemic steroids
Strep infection = guttate psoriasis
What are the features of lichen planus ?
- Itchy, papular rash most commonly on the palms, soles, genitalia and flexor surfaces of the arms.
- Polyglonal in shape - white lines pattern on the surface
- Kobner phenomenon
- Oral mucosa effected in half of patients (white lace pattern
-Thinning of the nail plate
How is lichen planus managed ?
Mainstay of treatment = potent topical steroids like clobetasol
Extensive may need oral steroids or immunosuppession
How is oral lichen planus managed
Benzydamine mouthwash or spray
What is impetigo ?
Superficial bacterial skin infection that is usually caused by staph aureus or strep pyrogenes.
How is impetigo spread ?
Direct contact with discharges from the scabs of an infected person. It is very infectious
What are the features of impetigo ?
- Golden, crusted skin lesions typically found around the mouth
What is the first line of treatment of impetigo in patients that are not systemically unwell or at high risk of complications ?
- Hydrogen peroxide 1 percent cream.
What is the treatment of impetigo in patients where hydrogen peroxide cream has not worked ?
topical fusidic acid
topical mupirocin should be used if fusidic acid resistance is suspected
What are the school exclusion guidelines for patients with impetigo ?
children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
What is one of the only causes of rash with pain in adults and what is the general treatment ?
Shingles
- May be infectious untill the vesicles crust over so isolation, paracetamol and NSAID and antivirals.
Oral corticosteroids may be advised in patients who are immunocompetent.
What is the treatment for guttae psoriasis ?
Most cases resolve spontaneously within 2-3 months
Topical agents if symptomatic and reassurance
What causes Eczema herpaticum ?
Severe primary infection of the skin by HSV1 or 2
How does eczema herpaticum present ?
Seen in children with atopic eczema and often presents as a rapidly progressing, painful rash.
Lesions will be erythematous, crusted and punched out erosions.
What is the management of eczema herpaticum ?
As it is potentially life-threatening children should be admitted for IV aciclovir.
What is the treatment for lyme disease ?
Oral doxycycline
When can lyme disease be diagnosed clinically ?
When there is a classical presentation - bullseye target lesion
What antibodies are tested in lyme disease ?
Borrelia antibodies
What is the treatment of tinea capitis (scalp ringworm) ?
Oral antifungals (like itraconazole)
Adjunct therapy with topical agents (ketoconazole)
Oral and topical antifungals.
What type of cancer is tamoxifen a risk factor for ?
Endometrial cancer
What is erythroderma ?
Dermatological emergency where there is widespread erythema affecting more than 90 percent of the skin surface. This can result in heat and fluid loss causing hypothermia and systemic symptoms.
What are the most common causes of erythroderma ?
The commonest causes are due to exacerbation of pre-existing skin conditions.
- Dermatitis - Atopic dermatitis, seborrhoeic dermatitis and contact dermatitis.
- Psoriasis
- Pityriasis rubra pilaris.
Can also be caused by drug allergies or idiopathic causes.
How is erythroderma managed ?
Supportive management (fluids, emollients and by treating the underlying disease)
- Dermatology refferal.
