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.
