Derm 1 (passmed) Flashcards
What’s the medical name for athletes foot? What causes it?
Tinea pedis.
fungi in the genus Trichophyton.
How do you treat athletes foot?
- Options include terbinafine cream or an imidazole such as clotrimazole, miconazole, or econazole cream (available over-the-counter for specific age-groups).
- Alternative options include over-the-counter undecenoic acid cream or topical preparations containing tolnaftate.
If an adult has severe or extensive disease, consider prescribing oral antifungal (oral terbinafine) treatment if there is:
- A positive skin sample fungal microscopy or culture result.
- A strong clinical suspicion of fungal foot infection before mycology results are back, depending on clinical judgement.
- A negative mycology result, but clinical features are very suggestive of infection.
- Arrange for repeat skin sampling, and start oral antifungal treatment.
What can cause pellagra?
Isoniazid
What is pellagra and what is it characterised by?
(vitamin B3 deficiency):
Diarrhoea
Dermatitis (brown scaly rash on sun-exposed sites - termed Casal’s necklace if around neck)
Dementia
Death
What’s the condition? How do you treat it?
pruritic condition associated with last trimester
lesions often first appear in abdominal striae
Polymorphic eruption of pregnancy
Management depends on severity: emollients, mild potency topical steroids and oral steroids may be used
What’s the condition? How is it treated?
- pruritic blistering lesions
- often develop in peri-umbilical region, later spreading to the trunk, back, buttocks and arms
- usually presents 2nd or 3rd trimester and is rarely seen in the first pregnancy
Pemphigoid gestationis
oral corticosteroids are usually required
What are the types of dermatitis?
Irritant contact dermatitis
- common - non-allergic reaction due to weak acids or alkalis (e.g. detergents).
- Often seen on the hands.
- Erythema is typical, crusting and vesicles are rare
Allergic contact dermatitis
- type IV hypersensitivity reaction.
- Uncommon - often seen on the head following hair dyes
- Presents as an acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself.
- Topical treatment with a potent steroid is indicated
What is the likely causative organism of pityriasis versicolor?
Malassezia furfur (fungus)
Treatment for pityriasis versicolor
- topical antifungal. NICE Clinical Knowledge Summaries advise ketoconazole shampoo as this is more cost effective for large areas
- if failure to respond to topical treatment then consider alternative diagnoses (e.g. send scrapings to confirm the diagnosis) + oral itraconazole
What are the features of pityriasis versicolor?
- most commonly affects trunk
- patches may be hypopigmented, pink or brown (hence versicolor). May be more noticeable following a suntan
- scale is common
- mild pruritus
What is a Marjolin’s ulcer?
a squamous cell carcinoma in an area with chronic inflammation
What are the risk factors for SCC?
- excessive exposure to sunlight / psoralen UVA therapy
- actinic keratoses and Bowen’s disease
- immunosuppression e.g. following renal transplant, HIV
- smoking
- long-standing leg ulcers (Marjolin’s ulcer)
- genetic conditions e.g. xeroderma pigmentosum, oculocutaneous albinism
How do you treat SCC?
Surgical excision with 4mm margins if lesion <20mm in diameter. If tumour >20mm then margins should be 6mm. Mohs micrographic surgery may be used in high-risk patients and in cosmetically important sites.
What are the good/poor prognostic features of SCC?
Good Well differentiated tumours <20mm diameter <2mm deep No associated diseases
Poor Poorly differentiated tumours >20mm in diameter >4mm deep Immunosupression for whatever reason
The following are features of what condition?
- typically on the lower limbs
- initially small red papule
- later deep, red, necrotic ulcers with a violaceous border
- may be accompanied systemic symptoms e.g. Fever, myalgia
Pyoderma gangrenosum
What are the causes of pyoderma gangrenosum?
- idiopathic in 50%
- inflammatory bowel disease: ulcerative colitis, Crohn’s
- rheumatoid arthritis, SLE
- myeloproliferative disorders
- lymphoma, myeloid leukaemias
- monoclonal gammopathy (IgA)
- primary biliary cirrhosis
How do you manage pyoderma gangrenosum?
- the potential for rapid progression is high in most patients and most doctors advocate oral steroids as first-line treatment
- other immunosuppressive therapy, for example ciclosporin and infliximab, have a role in difficult cases
How do you treat Eczema herpeticum?
Admit to hospital for IV antivirals (aciclovir)
What factors worsen psoriasis?
trauma
- alcohol
- drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
- withdrawal of systemic steroids
Which term is used to describe androgen-dependent hair growth?
Hirsutism
Which term is used to describe androgen-independent hair growth?
hypertrichosis
What are the causes of hirsutism?
A Cruising POD
- androgen therapy
- adrenal tumour
- androgen secreting ovarian tumour
- Cushing’s syndrome
- congenital adrenal hyperplasia
- PCOS
- obesity: thought to be due to insulin resistance
- drugs: phenytoin, corticosteroids
What are the causes of hypertrichosis?
- drugs: minoxidil, ciclosporin, diazoxide
- congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis
- porphyria cutanea tarda
- anorexia nervosa
How do you manage hirsutism?
- advise weight loss if overweight
- cosmetic techniques such as waxing/bleaching - not available on the NHS
- consider using combined oral contraceptive pills such as co-cyprindiol (Dianette) or ethinylestradiol and drospirenone (Yasmin). Co-cyprindiol should not be used long-term due to the increased risk of venous thromboembolism
- facial hirsutism: topical eflornithine - contraindicated in pregnancy and breast-feeding
What are the features of vitiligo?
- well demarcated patches of depigmented skin
- the peripheries tend to be most affected
- trauma may precipitate new lesions (Koebner phenomenon)
What is vitiligo?
Vitiligo is an autoimmune condition which results in the loss of melanocytes and consequent depigmentation of the skin. It is thought to affect around 1% of the population and symptoms typically develop by the age of 20-30 years.
Which conditions are associated with vitiligo?
- type 1 diabetes mellitus
- Addison’s disease
- autoimmune thyroid disorders
- pernicious anaemia
- alopecia areata
What’s the management for vitiligo?
- sun block for affected areas of skin
- camouflage make-up
- topical corticosteroids may reverse the changes if applied early
- there may also be a role for topical tacrolimus and phototherapy, although caution needs to be exercised with light-skinned patients
Which drugs exacerbate plaque psoriasis?
LAB NAT
Lithium Beta-blockers NSAIDs ACEi TNF-alpha inhibitors Anti-malarials
What are the skin features of SLE?
- photosensitive ‘butterfly’ rash
- discoid lupus
- alopecia
- livedo reticularis: net-like rash
What is bullous pemphigoid?
Bullous pemphigoid is an autoimmune condition causing sub-epidermal blistering of the skin. This is secondary to the development of antibodies against hemidesmosomal proteins BP180 and BP230
What are the features of bullous pemphigoid?
- itchy, tense blisters typically around flexures
- the blisters usually heal without scarring
- mouth is usually spared*
How do you manage bullous pemphigoid?
Management
- referral to dermatologist for biopsy and confirmation of diagnosis
- oral corticosteroids are the mainstay of treatment
- topical corticosteroids, immunosuppressants and antibiotics are also used
Skin biopsy
- immunofluorescence shows IgG and C3 at the dermoepidermal junction
What are the features of acne rosacea?
- typically affects nose, cheeks and forehead
- flushing is often first symptom
- telangiectasia are common
- later develops into persistent erythema with papules and pustules
- rhinophyma
- ocular involvement: blepharitis
How do you manage acne rosacea?
- topical metronidazole may be used for mild symptoms (i.e. Limited number of papules and pustules, no plaques)
- more severe disease is treated with systemic antibiotics e.g. Oxytetracycline
- recommend daily application of a high-factor sunscreen
- camouflage creams may help conceal redness
- laser therapy may be appropriate for patients with prominent telangiectasia
A 52-year-old African-American woman presents to the dermatology department. She has noticed a patch of pigmented skin on her toe, which has been slowly enlarging over the past five months. On examination, she has pigmentation of the nail bed of her great toe, affecting the adjacent cuticle and proximal nail fold. Which subtype of melanoma would you expect to present in this manner?
Acral lentiginous melanoma
What’s Hutchinson’s sign?
Pigmentation of nail bed affecting proximal nail fold suggests melanoma
What are the types of melanoma?
Superficial spreading 70% of cases
Nodular (most aggressive)
Lentigo maligna
Acral lentiginous (rare but most common in black people)
How do you treat melanoma?
- Suspicious lesions should undergo excision biopsy on the day with a 2mm margin. The lesion should be removed in completely as incision biopsy can make subsequent histopathological assessment difficult.
- Patient returns 3 weeks later (once pathology complete and case discussed at MDT meeting).
- Once the diagnosis is confirmed the pathology report should be reviewed to determine whether further re-excision of margins is required (see below):
- melanoma in situ. 5mm margin re-excision to fascia. Review for suture removal. Follow up for 3 months. Give melanoma shared care sheet. Arrange whole body screening photos. At 3/12 follow up discuss sun avoidance & skin surveillance. Vit D suppl. Check scar and discharge.
- Invasive melanoma <0.8 mm, no ulceration. 1 cm margin re-excision to fascia. Review for suture removal. Follow up for 3 months. Give melanoma shared care sheet. Arrange whole body screening photos. At 3/12 follow up discuss sun avoidance & skin surveillance. Vit D suppl. Check scar, lymph nodes and skin. Follow shared care protocol for 12 months then discharge.
- Invasive melanoma >0.8 mm or ulcerated. Refer to plastics. offer SNLB and WLE. 5 yr follow up. Plastics refer to oncology
Margins of excision-Related to Breslow thickness
Lesions 0-1mm thick- 1cm
Lesions 1-2mm thick- 1- 2cm (Depending upon site and pathological features)
Lesions 2-4mm thick- 2-3 cm (Depending upon site and pathological features)
Lesions >4 mm thick- 3cm
Further treatments such as sentinel lymph node mapping, isolated limb perfusion and block dissection of regional lymph node groups should be selectively applied.
What is dermatitis herpetiformis?
Dermatitis herpetiformis is an autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.
What are the features of dermatitis herpetiformis?
itchy, vesicular skin lesions on the extensor surfaces (e.g. elbows, knees, buttocks)
How do you diagnose and treat dermatitis herpetiformis?
Diagnose
- skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis
Management
- gluten-free diet
- dapsone
What are the features of lichen planus?
- Ps: purple, pruritic, papular, polygonal rash on flexor surfaces, palms, soles, genitalia.
- ‘white-lace’ pattern (Wickham’s striae) over surface.
- Oral involvement common (50% of patients)
- Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
- nails: thinning of nail plate, longitudinal ridging
What are the features of lichen sclerosus?
itchy white spots typically seen on the vulva of elderly women
What’s the management for lichen planus?
- topical steroids are the mainstay of treatment
- benzydamine mouthwash or spray is recommended for oral lichen planus
- extensive lichen planus may require oral steroids or immunosuppression
What’s the prevalence of psoriasis?
2%
What’s the pathophysiology of psoriasis?
- multifactorial and not yet fully understood
genetic: associated HLA-B13, -B17, and -Cw6. Strong concordance (70%) in identical twins - immunological: abnormal T cell activity stimulates keratinocyte proliferation. There is increasing evidence this may be mediated by a novel group of T helper cells producing IL-17, designated Th17. These cells seem to be a third T-effector cell subset in addition to Th1 and Th2
- environmental: it is recognised that psoriasis may be worsened (e.g. Skin trauma, stress), triggered (e.g. Streptococcal infection) or improved (e.g. Sunlight) by environmental factors
What are the subtypes of psoriasis?
Plaque psoriasis: the most common sub-type resulting in the typical well demarcated red, scaly patches affecting the extensor surfaces, sacrum and scalp
Flexural psoriasis: in contrast to plaque psoriasis the skin is smooth
Guttate psoriasis: transient psoriatic rash frequently triggered by a streptococcal infection. Multiple red, teardrop lesions appear on the body
Pustular psoriasis: commonly occurs on the palms and soles
What is the most likely diagnosis in an uncircumcised man, who has developed a tight white ring around the tip of the foreskin and phimosis?
Lichen sclerosis
What should you do if a child presents with a new purpuric rash?
Admitted immediately for investigations as it may be a sign of meningococcal septicaemia or acute lymphoblastic leukaemia
What are the causes of a purpuric rash?
Children
• Meningococcal septicaemia
• Acute lymphoblastic leukaemia
- Congenital bleeding disorders
- Immune thrombocytopenic purpura
- Henoch-Schonlein purpura
- Non-accidental injury • Immune thrombocytopenic purpura
Adults
• Bone marrow failure (secondary to leukaemias, myelodysplasia or bone metastases)
• Senile purpura
• Drugs (quinine, antiepileptics, antithrombotics)
• Nutritional deficiencies (vitamins B12, C and folate)
Raised superior vena cava pressure (e.g. secondary to a bad cough) may cause petechiae in the upper body but would not cause purpura.
What are the zones of a burn?
Jackson model:
- coagulation (maximum damage, irreversible tissue loss, coagulative necrosis)
- stasis (decreased tissue perfusion, zone salvagable)
- hyperaemia (tissue perfusion is increased)
Which layers are damaged in a superficial burn?
Epidermis
Upper dermis
- Includes damage to keratinocytes and an immune response.
- Inflammation triggers nociceptors, causing pain.
- Some cytokines cause increased permeability and fluid leaks out of vessels -> interstitial oedema/hypotension
- If fluid leaks out in one area a blister is formed
- Vasodilation causes warmth, blanching and erythema
Which layers are damaged in a deep burn?
Epidermis to the hypodermis
- blood vessels damaged so everything leaks out causing dry, non-blanching and inelastic surface
- nerve fibres can be damaged leading to hypoesthesia
- fluid can leak out if remaining blood vessels causing shock
What can you do to assess the extent of a burn?
Wallace's Rule of Nines: head + neck = 9% each arm = 9% each anterior part of leg = 9% each posterior part of leg = 9% anterior chest = 9% posterior chest = 9% anterior abdomen = 9% posterior abdomen = 9%
Lund and Browder chart: the most accurate method
the palmar surface is roughly equivalent to 1% of total body surface area (TBSA). Not accurate for burns > 15% TBSA
When should IV fluid resuscitation be used for burns? How much should you give?
IV fluids are not required for first degree (i.e. superficial, epidermal) burns
Intravenous fluids will be required for children with burns greater than 10% of total body surface area. Adults with burns greater than 15% of total body surface area will also require IV fluids.
The fluids are calculated using the Parkland formula which is; volume of fluid= total body surface area of the burn % x weight (Kg) x4.
Half of the fluid is administered in the first 8 hours. A urinary catheter should be inserted. Analgesia should be given.
Complex burns, burns involving the hand perineum and face and burns >10% in adults and >5% in children should be transferred to a burns unit.
When should you refer someone with burns to secondary care?
- all deep dermal and full-thickness burns.
- superficial dermal burns of more than 3% TBSA in adults, or more than 2% TBSA in children
- superficial dermal burns involving the face, hands, feet, perineum, genitalia, or any flexure, or circumferential burns of the limbs, torso, or neck
- any inhalation injury
- any electrical or chemical burn injury
- suspicion of non-accidental injury
What are the categories of burns based on depth and how do they appear?
Superficial epidermal
First degree
Red and painful
Partial thickness (superficial dermal)
Second degree
Pale pink, painful, blistered
Partial thickness (deep dermal)
Second degree
Typically white but may have patches of non-blanching erythema. Reduced sensation
Full thickness
Third degree
White/brown/black in colour, no blisters, no pain
What’s the term for excessive production of sweat?
Hyperhidrosis
What are the management options for hyperhidrosis?
- topical aluminium chloride preparations are first-line. Main side effect is skin irritation
- iontophoresis: particularly useful for patients with palmar, plantar and axillary hyperhidrosis
- botulinum toxin: currently licensed for axillary symptoms
- surgery: e.g. Endoscopic transthoracic sympathectomy. Patients should be made aware of the risk of compensatory sweating
What is acanthosis nigricans?
Symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin
What are the causes of acanthosis nigricans?
- gastrointestinal cancer
- diabetes mellitus
- obesity
- polycystic ovarian syndrome
- acromegaly
- Cushing’s disease
- hypothyroidism
- familial
- Prader-Willi syndrome
- drugs: oral contraceptive pill, nicotinic acid
A 36-year-old female with a history of ulcerative colitis is diagnosed as having pyoderma gangrenosum. She presented 4 days ago with a 3 cm lesion on her right shin which rapidly ulcerated and is now painful. How should you manage the condition?
Oral prednisolone
What is Chondrodermatitis nodularis helicis?
Chondrodermatitis nodularis helicis (CNH) is a common and benign condition characterised by the development of a painful nodule on the ear. It is thought to be caused by factors such as persistent pressure on the ear (e.g. secondary to sleep, headsets), trauma or cold. CNH is more common in men and with increasing age.
How do you manage chondrodermatitis nodularis helicis?
- reducing pressure on the ear: foam ‘ear protectors’ may be used during sleep
- other treatment options include cryotherapy, steroid injection, collagen injection
- surgical treatment may be used but there is a high recurrence rate
A 28-year-old Caucasian male presents with itchy red spots on is abdomen, back and arms, which he reports appeared quite suddenly. He has no significant past medical history, but states he had a sore throat a few weeks ago. On examination, you notice he has a white pus-like discharge over his palatine tonsils. He states that he a similar rash last winter, when he had a sore throat.
Which of the following is the most likely diagnosis?
Streptococcal throat infection may precipitate psoriasis (particularly guttate psoriasis). Patients with frequent exacerbations of guttate psoriasis due to streptococcal throat infections may benefit from tonsillectomy
What’s the treatment for alopecia areata?
Hair will regrow in 50% of patients by 1 year, and in 80-90% eventually. Careful explanation is therefore sufficient in many patients.
Other treatment options include:
- topical or intralesional corticosteroids
- topical minoxidil
- phototherapy
- dithranol
- contact immunotherapy
- wigs
What’s the treatment for athlete’s foot?
Clinical knowledge summaries recommend a topical imidazole, undecenoate, or terbinafine first-line
e.g Topical miconazole
What is HHT?
Hereditary haemorrhagic telangiectasia (Also known as Osler-Weber-Rendu syndrome)
- autosomal dominant condition
- characterised by (as the name suggests) multiple telangiectasia over the skin and mucous membranes
- 20% of cases occur spontaneously without prior FHx
How do you diagnose HHT?
There are 4 main diagnostic criteria. If the patient has 2 then they are said to have a possible diagnosis of HHT. If they meet 3 or more of the criteria they are said to have a definite diagnosis of HHT:
- epistaxis : spontaneous, recurrent nosebleeds
- telangiectases: multiple at characteristic sites (lips, oral cavity, fingers, nose)
- visceral lesions: for example gastrointestinal telangiectasia (with or without bleeding), pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM
- family history: a first-degree relative with HHT
How would you investigate and manage a non-healing ulcer?
Investigations
- ankle-brachial pressure index (ABPI) is important in non-healing ulcers to assess for poor arterial flow which could impair healing
- a ‘normal’ ABPI may be regarded as between 0.9 - 1.2. Values below 0.9 indicate arterial disease. Interestingly, values above 1.3 may also indicate arterial disease, in the form of false-negative results secondary to arterial calcification (e.g. In diabetics)
Management for venous ulcer
- compression bandaging, usually four layer (only treatment shown to be of real benefit)
- oral pentoxifylline, a peripheral vasodilator, improves healing rate
- small evidence base supporting use of flavinoids
- little evidence to suggest benefit from hydrocolloid dressings, topical growth factors, ultrasound therapy and intermittent pneumatic compression
What is leukoplakia?
- Leukoplakia is a premalignant condition which presents as white, hard spots on the mucous membranes of the mouth
- more common in smokers
Leukoplakia is said to be a diagnosis of exclusion. Candidiasis and lichen planus should be considered, especially if the lesions can be ‘rubbed off’
Biopsies are usually performed to exclude alternative diagnoses such as squamous cell carcinoma and regular follow-up is required to exclude malignant transformation to squamous cell carcinoma, which occurs in around 1% of patients.
What is the name for the rash that is caused by infrared radiation and is commonly associated with hot water bottles or open fires?
Erythema ab igne
Do telangiectasia blanch?
yes
Which rash is associated with coeliac disease?
Dermatitis herpetiformis
What causes onychomycosis nail infections?
- dermatophytes - mainly Trichophyton rubrum, accounts for 90% of cases
- yeasts - such as Candida
- non-dermatophyte moulds
How would you treat onychomycosis? How long for? How successful is it?
- treatment is successful in around 50-80% of people
diagnosis should be confirmed by microbiology before starting treatment - dermatophyte infection: oral terbinafine is currently recommended first-line with oral itraconazole as an alternative. Six weeks - 3 months therapy is needed for fingernail infections whilst toenails should be treated for 3 - 6 months
- Candida infection: mild disease should be treated with topical antifungals (e.g. Amorolfine) whilst more severe infections should be treated with oral itraconazole for a period of 12 weeks
Where is lichen planus most common?
- flexor surfaces of arms
- palms
- genitalia
- soles
What does the lichen planus rash look like?
polygonal in shape, ‘white-lace’ pattern on the surface (Wickham’s striae)
How do you treat lichen planus?
- topical steroids are the mainstay of treatment
- benzydamine mouthwash or spray is recommended for oral lichen planus
- extensive lichen planus may require oral steroids or immunosuppression
What’s the condition?
- target lesions
- initially seen on the back of the hands / feet before spreading to the torso
- upper limbs are more commonly affected than the lower limbs
- pruritus is occasionally seen and is usually mild
Erythema multiforme
What causes erythema multiforme?
- viruses: herpes simplex virus (the most common cause), Orf (a skin disease of sheep and goats caused by a parapox virus)
- idiopathic
- bacteria: Mycoplasma, Streptococcus
- drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
connective tissue disease e.g. Systemic lupus erythematosus - sarcoidosis
- malignancy
What is the most common malignancy associated with acanthosis nigricans?
Gastrointestinal adenocarcinoma
What’s the condition and what’s it associated with?
- herald patch (usually on trunk)
- followed by erythematous, oval, scaly patches which follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer. This may produce a ‘fir-tree’ appearance
Pityriasis rosea
herpes hominis virus 7 (HHV-7) may play a role
How do you manage pityriasis rosea?
self-limitingm - usually disappears after 6-12 weeks
What are the causes of erythema nodosum?
- infection: streptococci, TB, brucellosis
- systemic disease: sarcoidosis, inflammatory bowel disease, Behcet’s
- malignancy/lymphoma
- drugs: penicillins, sulphonamides, combined oral contraceptive pill
- pregnancy
How do you manage burns?
- superficial epidermal: symptomatic relief - analgesia, emollients etc
- superficial dermal: cleanse wound, leave blister intact, non-adherent dressing, avoid topical creams, review in 24 hours
A 67-year-old retired gardener presents to the dermatology department with a suspicious evolving freckle on his face, which he first noticed 10 years ago. On examination, he has a 3cm asymmetric pigmented patch on his cheek, comprised of multiple shades of brown and black, and with asymmetrical thickening of the lesion. Which subtype of melanoma is this gentleman most likely to have?
Lentigo maligna melanoma: Suspicious freckle on face or scalp of chronically sun-exposed patients
How long can you expect to itch for after scabies?
It is normal for pruritus to persist for up to 4-6 weeks post eradication
What causes scabies?
- the mite Sarcoptes scabiei
- spread by prolonged skin contact
The scabies mite burrows into the skin, laying its eggs in the stratum corneum. The intense pruritus associated with scabies is due to a delayed type IV hypersensitivity reaction to mites/eggs which occurs about 30 days after the initial infection.
What are the features of scabies?
- widespread pruritus
- silvery lines with a dot at one end (linear burrows) on the side of fingers, interdigital webs and flexor aspects of the wrist
- rash spreads and turns into tiny red spots
- rash anywhere on body apart from head
- in infants the face and scalp may also be affected
- secondary features are seen due to scratching: excoriation, infection
How do you manage scabies and what advice do you give to patients?
Management
- permethrin 5% is first-line
- malathion 0.5% is second-line
- give appropriate guidance on use (see below)
- pruritus persists for up to 4-6 weeks post eradication
Patient guidance on treatment (from Clinical Knowledge Summaries)
- avoid close physical contact with others until treatment is complete
- all household and close physical contacts should be treated at the same time, even if asymptomatic
- launder, iron or tumble dry clothing, bedding, towels, etc., on the first day of treatment to kill off mites.
The BNF advises to apply the insecticide to all areas, including the face and scalp, contrary to the manufacturer’s recommendation. Patients should be given the following instructions:
- apply the insecticide cream or liquid to cool, dry skin
pay close attention to areas between fingers and toes, under nails, armpit area, creases of the skin such as at the wrist and elbow
- allow to dry and leave on the skin for 8-12 hours for permethrin, or for 24 hours for malathion, before washing off
- reapply if insecticide is removed during the treatment period, e.g. If wash hands, change nappy, etc
repeat treatment 7 days later
What are the features of a pyogenic granuloma?
- Overgrowth of blood vessels.
- Red nodules.
- Usually follow trauma.
- May mimic amelanotic melanoma
What causes impetigo and where and when does it normally occur?
- Staphylcoccus aureus or Streptococcus pyogenes
- It can be a primary infection or a complication of an existing skin condition such as eczema (in this case), scabies or insect bites.
- lesions tend to occur on the face, flexures and limbs not covered by clothing
- Impetigo is common in children, particularly during warm weather.
How do you manage impetigo?
Limited, localised disease
- topical fusidic acid (antibiotic) is first-line
- topical retapamulin is used second-line if fusidic acid has been ineffective or is not tolerated
- MRSA is not susceptible to either fusidic acid or retapamulin. Topical mupirocin (Bactroban) should therefore be used in this situation
Extensive disease
- oral flucloxacillin
- oral erythromycin if penicillin allergic
- children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
What’s the incubation period of impetigo?
between 4 to 10 days
How should emollients be applied?
- Initially applying emollients 2-3 times per day (including immediately after washing)
- When skin worsens emollients can be applied hourly
- Wash hands before applying emollient to prevent infection of damaged skin
- Either dispense emollient using a pump or spoon from a tub to avoid contamination of the tub.
- Apply emollient generously to all areas of the body onto the skin in a downward motion in direction of hair
- Do not rub in emollients, but rather leave them to soak in.
What are prognostic markers for severe disease in eczema?
- onset at age 3-6 months
- severe disease in childhood
- associated asthma or hay fever
- small family size
- high IgE serum levels
How do you manage eczema?
- emollients
- topical steroids
- UV radiation
- immunosuppressants: e.g. ciclosporin, antihistamines and azathioprine
Is Nikolsky’s sign positive or negative in TEN
positive: the epidermis separates with mild lateral pressure (i.e blister pops so the lesion is within the epidermis)
Which drugs are known to induce toxic epidermal necrosis (TEN)?
phenytoin sulphonamides allopurinol penicillins carbamazepine NSAIDs
How do you manage TEN?
- stop precipitating factor
- supportive care, often in intensive care unit
- intravenous immunoglobulin has been shown to be effective and is now commonly used first-line
- other treatment options include: immunosuppressive agents (ciclosporin and cyclophosphamide), plasmapheresis
