Dermatology Flashcards
What is eczema?
Describe its typical appearance?
Eczema is a chronic atopic condition caused by defects in the normal continuity of the skin barrier, leading to inflammation in the skin. There is a genetic component to eczema and it tends to run in families, however there is no single inheritance pattern. It has significant variation in the severity of the condition. Some patients can have very occasional mild patches that respond well to emollients, where others have large areas of skin that are severely affected and require strong topical steroids or systemic treatments.
Eczema usually presents in infancy with dry, red, itchy and sore patches of skin over the flexor surfaces (the inside of elbows and knees) and on the face and neck. Patients with eczema experience periods where the condition is well controlled and periods where the eczema is more problematic, known as flares.
Underpinned by a genetic defect in skin barrier function
– Associated with a loss of function variant of protein filaggrin.
– This leads to decreased ceramide lipids in skin leading to breakdown of skin barrier and escape of moisture
– This allows irritants to enter and activate inflammasomes.
Appearance:
– Erythematous, indistinct fissuring (cracks) through the epidermis
– For babies, lesions more concentrated around the face and the torso. – As children get older, lesions are more likely to be found in the flexor surfaces (elbows, behind knees) and the creases of the face.
– This is because sweat concentrates here causing more irritation.
What is the managemnt of Eczema?
Management
Management can be thought of as maintenance and management of flares, similar to the management of chronic and acute asthma.
The key to maintenance is to create an artificial barrier over the skin to compensate for the defective skin barrier. This is done using emollients that are as thick and greasy as tolerated, used as often as possible, particularly after washing and before bed. Patients should avoid activities that break down the skin barrier, such as bathing in hot water, scratching or scrubbing their skin and using soaps and body washes that remove the natural oils in the skin. Emollients or specifically designed soap substitutes can be used instead of soap and body washes when showering or washing hands.
Some patients find certain environmental factors play a role in making their eczema symptoms worse or better. For example, it may completely resolve on holiday in warm, humid countries, only to flare on returning to the cold air in the UK. Environmental triggers, such as changes in temperature, certain dietary products, washing powders, cleaning products and emotional events or stresses can also play a role.
Flares can be treated with thicker emollients, topical steroids, “wet wraps” (covering affected areas in a thick emollient and applying a wrap to keep moisture locked in overnight) and treating any complications such as bacterial or viral infections. Very rarely IV antibiotics or oral steroids might be required in very severe flares.
Other specialist treatments in severe eczema include zinc impregnated bandages, topical tacrolimus, phototherapy and systemic immunosuppressants, such as oral corticosteroids, methotrexate and azathioprine.
Emollients
Depending on the severity of the eczema, some patients may only require thin emollients to maintain their skin barrier, whilst others with more severe eczema require very thick greasy emollients. The general rule is to use emollients that are as thick as tolerated and required to maintain the eczema.
Thin creams:
- E45
- Diprobase cream
- Oilatum cream
- Aveeno cream
- Cetraben cream
- Epaderm cream
Thick, greasy emollients:
- 50:50 ointment (50% liquid paraffin)
- Hydromol ointment
- Diprobase ointment
- Cetraben ointment
- Epaderm ointment
Topical Steroids
The general rule is to use the weakest steroid for the shortest period required to get the skin under control. Steroids are very good for settling down the immune activity in the skin and reducing inflammation, but they do come with side effects. They can lead to thinning of the skin, which in turn make the skin more prone to flares, bruising, tearing, stretch marks and enlarged blood vessels under the surface of the skin called telangiectasia. Depending on the location and strength of the steroid there may be some systemic absorption of the steroid. The risks of using steroids need to be balanced against the risk of poorly controlled eczema.
The thicker the skin, the stronger the steroid required. Only weak steroids used very cautiously should be applied to areas of thin skin such as the face, around the eyes and in the genital region. It is best to completely avoid steroids in these areas in children.
The steroid ladder from weakest to most potent:
- Mild: Hydrocortisone 0.5%, 1% and 2.5%
- Moderate: Eumovate (clobetasone butyrate 0.05%)
- Potent: Betnovate (betamethasone 0.1%)
- Very potent: Dermovate (clobetasol propionate 0.05%)
What is eczema herpeticum?
What is the management?
Eczema herpeticum is a viral skin infection caused by the herpes simplex virus (HSV) or varicella zoster virus (VZV). It was previously known as Kaposi varicelliform eruption (don’t confuse this with Kaposi sarcoma, which occurs in late stage HIV). Herpes simplex virus 1 (HSV-1) is the most common causative organism, and may be associated with a coldsore in the patient or a close contact. It usually occurs in a patient with a pre-existing skin condition, such as atopic eczema or dermatitis, where the virus is able to enter the skin and cause an infection.
Presentation
A typical presentation is a patient who suffers with eczema that has developed a widespread, painful, vesicular rash with systemic symptoms such as fever, lethargy, irritability and reduced oral intake. There will usually be lymphadenopathy (swollen lymph nodes).
The Rash
The rash is usually widespread and can affect any area of the body. It is erythematous, painful and sometimes itchy, with vesicles containing pus. The vesicles appear as lots of individual spots containing fluid. After they burst, they leave small punched-out ulcers with a red base.
Management
Viral swabs of the vesicles can be used to confirm the diagnosis, although treatment is usually started based on the clinical appearance.
Treatment is with aciclovir. A mild or moderate case may be treated with oral aciclovir, whereas more severe cases may require IV aciclovir.
Describe the appearance of psoriasis
What is the management?
Patches of psoriasis are dry, flaky, scaly, faintly erythematous skin lesions that appear in raised and rough plaques, commonly over the extensor surfaces of the elbows and knees and on the scalp. These skin changes are caused by the rapid generation of new skin cells, resulting in an abnormal buildup and thickening of the skin in those areas.
Plaque psoriasis features the thickened erythematous plaques with silver scales, commonly seen on the extensor surfaces and scalp. The plaques are 1cm – 10cm in diameter. This is the most common form of psoriasis in adults.
Guttate psoriasis is the second most common form of psoriasis and commonly occurs in children. It presents with many small raised papules across the trunk and limbs. The papules are mildly erythematous and can be slightly scaly. Over time the papules in guttate psoriasis can turn into plaques. Guttate psoriasis is often triggered by a streptococcal throat infection, stress or medications. It often resolves spontaneously within 3 – 4 months.
Management
Management depends on the severity of the condition. Psoriasis in children is usually managed and followed up by a specialist. It can be difficult to treat and psychosocial support is very important. The treatment options include:
- Topical steroids
- Topical vitamin D analogues (calcipotriol)
- Topical dithranol
- Topical calcineurin inhibitors (tacrolimus) are usually only used in adults
- Phototherapy with narrow band ultraviolet B light is particularly useful in extensive guttate psoriasis
Rarely, where topical treatments fail with severe and difficult to control psoriasis, children may be started on unlicensed systemic treatment under the guidance of an experienced specialist. This might include methotrexate, cyclosporine, retinoids or biologic medications.
There are two products that contain both a potent steroid and vitamin D analogue that are commonly prescribed and worth being aware of. These not licensed in children and will be guided by a specialist.
Dovobet
Enstilar
What is acne vulgaris?
If condition is bad, what is the management?
This is a condition where there is increased sebum production due to increased androgens
– This causes excess keratin production which block follicles making comedones
-Anaerobic bacteria Propionibacterium acnes colonise plugs giving inflammation
Management:
– 1st line is single topical creams –> Benzoyl peroxide (antimicrobial action) or Vitamin A derivative
– If not successful –> try multiple topical agents together
– If still uncontrolled –> oral antibiotics – tetracyclines (unless pregnant or under 12, so use erythromycin)
– In women, can use combined oral contraceptive pill with oestrogen + anti-androgenic progestogen
– If uncontrolled –> refer to dermatology for oral isotretinoin (Vitamin A derivative)
– This is the most successful treatment but needs monitoring of LFTs, mood and must not get pregnant.
What is bullous pemphigold?
Describe its appearance
What is the management?
Bullous pemphigoid
This is an autoimmune skin condition causing blisters under the epidermis.
– Due to a type II hypersensitivity reaction which gives destruction of hemi- desmosomes between basal cells and basal membrane.
– IgG antibody is directed against BP180 and BP 230 of basement membrane – More common in elderly patients >70 years but there is no obvious cause
Appearance
– Starts as a non-specific rash a month before the blisters
– Then itchy blisters form around the skin folds.
– Blisters are sup-epidermal and quite tense (do not rupture very easily) and heal without scarring – Blisters contains clear or cloudy yellowish fluid, but rarely affect the mouth/genital areas.
– Nikolsky sign negative
**Management **
Corticosteroids to reduce blisters –> followed by immunosuppressants to wean off steroids
What is cellulitis?
Describe the appearance
What is the management?
Cellulitis is used to describe inflammation of the deep dermis and subcutaneous tissue
– Usually due to Streptococcus pyogenes or Staphylococcus Aureus
Appearance
– Usually seen on lower limbs affecting one leg
– Gives acute onset red, tender swollen skin that rapidly spreads
– Can have associated systemic upset e.g. fever, nausea
– Usually non-purulent (S, pyogenes) or purulent if Staph. Aureus.
Management
– Graded by Eron Classification according to systemic upset
– If < class 2 (systemically well) ➔ oral flucloxacillin
– If class 3 or more, or <1-year-old, or facial cellulitis ➔ admit to hospital for IV antibiotics due to sepsis risk
What is Lichen planus?
Describe its appearance
Lichen planus is a common, pruritic rash seen in adults, thought to be autoimmune.
– Results in a very itchy rash most commonly found on the wrists, ankles and the lumbar region, but can be widespread.
– Can also be caused by graft vs host disease, and drugs like thiazide diuretics and quinine
Appearance:
– Itchy planar, polygonal, purple papules (no fluid)
– Often has white reticular lines on surface (Wickham striae)
– Half of patients have involvement of the mouth, especially on the buccal mucosa with a white lacework pattern. – Lesions also are seen on the female genitalia, the penis and the nails
– Lesions demonstrate Koebner phenomenon –> where new lesions appear at the site of minor injury
**Management: **steroids
What is melanoma?
Describe its appearance
What is the treatment?
Malignant melanoma is a malignant neoplasm of melanocytes, which occurs in 2 phases:
i) Radial growth along epidermis and superficial dermis
ii) Vertical growth into deep dermis
– Most frequent mutation is in BRAF which leads to uncontrolled cell division
Appearance – Starts as an unusual freckle/mole but then becomes abnormal with ABCD:
– Asymmetry
– Borders irregular
– Colour not uniform
– Diameter >6mm
Suspect melanoma if:
– Change in size, shape, colour, or sensation
– Diameter >6mm or if the lesion is oozing or bleeding
Treatment – Excision biopsy + sentinel lymph node mapping
What is necrotising fascitis?
What are the symptoms?
What is the treatment?
Necrotising fasciitis is a bacterial infection of the subcutaneous tissue and fascia which covers muscles.
Bacteria release toxins which cause thrombosis of blood vessels.
– This leads to complete necrosis of the tissue and fascia.
– Type 1 –> Commonest type due to mixture of bacteria
– Usually seen in elderly patients with comorbidities (diabetes)
– Type 2 –> due to haemolytic group A Streptococcus e.g. S. Pyogenes
– Type 3 –> due to clostridium perfringens giving gas gangrene
Symptoms
– Development of a painful, red lesion within 24 hours of minor injury
– Usually seen on the limbs and perineum, giving a rapidly worsening cellulitis
– The pain is very severe, out of proportion to physical signs
– Lesion spreads almost like it is eating away the skin and can quickly lead to sepsis and toxic shock.
Management
– Admit to intensive care unit and IV antibiotics
– Surgical debridement ASAP to remove all necrotic tissue (usually repeated multiple times for a few days)
What is neurofibramatosis?
What are its features?
Neurofibromatosis Type 1 (NF1) (von Recklinghausen disease)
This is a complex multi-system disorder, caused by loss of protein Neurofibromin needed in many cells
– An autosomal dominant condition which is caused by a mutation/deletion of NF-1 gene on Chromosome 17
Skin features:
>5 Café au lait marks >1.5cm diameter (uniformly pigmented brown macules)
– Due to a collection of pigment producing melanocytes in the epidermis of the skin
– Freckles found in the axilla and groin region
– Peripheral neurofibromas
Other Organs:
– Spine –> Scoliosis
– Eye –> Lisch nodules (dome shaped gelatinous masses on iris surface)
– Endocrine –> Pheochromocytoma (adrenaline secreting tumour of the chromaffin cells)
Associations:
– Can lead to learning disabilities
– Hypertension – due to renal artery stenosis + phaeochromocytoma
– Tumours – Neurofibromas + Optic nerve gliomas
What is scabies?
Describe the apperance
A condition due to the mite Sarcoptes scabiei seen in young adults and children
– The mite colonises the skin and lays eggs within the epidermis.
– This then leads to a type 4 hypersensitivity reaction to the eggs which can occur up to a month after initial exposure, usually by direct skin-skin contact
– This causes the release of inflammatory cytokines giving rise to a widespread itch.
Scabies presents with incredibly itchy small red spots, possibly with track marks where the mites have burrowed. The classic location of the rash is between the finger webs, but it can spread to the whole body.
TOM TIP: Scabies is more common than you may think. When someone presents with an itchy rash, ask whether anyone they live with has a similar rash and check between their finger webs for little red dots and track marks that may indicate scabies.
Appearance
Linear burrows (wavy, thread-like grey lines that can have a small vesicle with a
black do at the end). Seen on fingers, wrists and penis.
– Rash (erythematous papules) on side of fingers, web spaces and under the nails
Management
Treatment is with permethrin cream. This needs to be applied to the whole body, completely covering skin. It is best to do this when the skin is cool (i.e. not after a bath or shower) so that a layer of cream remains on top of the skin and does not get absorbed. The cream should be left on for 8 – 12 hours and then washed off. This should be repeated a week later to kill all the eggs that survived the first treatment and have now hatched.
Oral ivermectin as a single dose that can be repeated a week later is an option for difficult to treat or crusted scabies.
Scabies is contagious to all household and close contacts. When one person is diagnosed, all household and close contacts should also be treated in exactly the same way, even if asymptomatic. This is because they may be infected and not yet have symptoms.
All clothes, bedclothes, towels and other materials in contact with scabies need to be washed on a hot wash to destroy the mites. Thorough hoovering of carpets and furniture is also essential.
Itching can continue for up to 4 weeks after successful treatment. Crotamiton cream and chlorphenamine at night at night can help with the itching.
Crusted Scabies
Crusted scabies is also known as Norwegian scabies. It is a serious infestation with scabies in patients that are immunocompromised. These patient may have over a million mites in their skin. They are extremely contagious. Rather than individual spots and burrows, they have patches of red skin that turn into scaly plaques. These can be misdiagnosed as psoriasis. Immunocompromised patients may not have an itch as they do not mount an immune response to the infestation. They may need admission for treatment as an inpatient with oral ivermectin and isolation.
