DERM Revision 3

Question 2

Describe what is meant by bullous pemphigoid [1]

It is caused by antibodies agaisnt which basement membrane proteins? [2]

Which patients is it commonly found in?

Answer 2

In frail patients
Autoimmune blistering condition
Antibodies against basement membrane proteins which are key components of hemidesmosomes
* BP 180
* BP 230

Question 3

Which neurological conditions is Bullous Pemphigoid associated with? [3]

Which medications are Bullous Pemphigoid associated with? [2]

Answer 3

Neurological disease (that cause frailty)
* Stroke
* Dementia
* Parkinson’s Disease

Drugs:
* PD-1 Inhibitors (used in the treatment of metastatic melanoma)
* Gliptins (diabetic medication)

Question 4

Describe the clinical manifestations of Bullous Pemphigoid [5]

Answer 4

• Severe itch
• Pre-bullous rash
• Large tense bullae and erosions on rupture
• Milia in healed areas
• Multple, large tense blisters - that leave eriosions after they burst
• Mucosal lesions uncommon

NB: top right shows the erosion after a blister has gone

Question 5

Describe the topical treatments [4] and systemic therapy [5] used to treat Bullous Pemphigoid

Answer 5

Topical Treatments
* Super potent topical steroid
* Non adhesive dressings
* Potassium per manganate soaks
* Pop large blisters

Systemic therapy
* Antihistamines
* Tetracycline antibiotic vs oral steroid (BLISTER trial)
* Methotrexate
* Mycophenolate Mofetil
* Biologic therapy - Rituxumab

Question 6

Describe the pathophysiology of Pemphigus Vulgaris [1]

Answer 6

Autoimmune blistering condition
- Autoantibodies to Desmoglein-3 (and sometimes also Desmoglein-1) which are found in desmosomes
- The autoantibodies belong to the IgG class, specifically IgG4

Question 7

Describe the clinical features of pemphigus vulgaris [+]

Answer 7

• Mucosal involvement usually precedes skin involvement – mouth + genitals: oral lesions are common and often present as the initial clinical feature.
• Thin-walled flaccid blisters filled with clear fluid
• Rupture easily
• Itchy, painful erosions
• Painful ! :( - epidermis has gone and exposing the dermis
• Often lose weight (due to mouth ulcers stopping eating)

Question 8

Which drugs can induce PV? [2]

Answer 8

Penicillamine
ACE-inhibitors

Question 9

Dx of Pemphigus Vulgaris ?

Answer 9

Punch/incisional biopsy of:
* Lesional skin for H&E
* Peri-lesional skin direct immunofluorescence
- Fishnet pattern of intercellular IgG and C3 deposits within the epidermis

Serum Autoantibody Testing:
- test measures circulating autoantibodies against desmoglein 1 and 3

Question 10

Tx of Pemphigus Vulgaris? [4]

Answer 10

First-Line Treatment
- oral corticosteroid ± azathioprine or mycophenolate

Second line:
- Rituximab

Intravenous immunoglobulin (IVIG) and plasmapheresis are adjunctive therapies for severe or refractory cases.

Patients on high-dose steroids or other immunosuppressants should receive prophylaxis against Pneumocystis jirovecii pneumonia with co-trimoxazole.

Notes: BMJ BP

Question 11

Tx for Dermatitis Herpetiformis? [2]

Answer 11

Gluten free diet for life
Dapsone

Question 12

Define erythroderma [1]

Name 5 causes

Answer 12

Widespread erythema of skin (over 90% of body surface area)

Causes
* Idiopathic (30%)
* Adverse drug reaction (gold)
* Known inflammatory skin disease (eczema, psoriasis)
* Cutaneous lymphoma

Question 13

Tx for Eczema Herpeticum? [2]

Answer 13

Acyclovir
Flucoxacillin

Question 14

What commonly causes erytherma multiforme? [3]

Describe the two types (EM minor/major) [2]

Answer 14

Causes:
Drugs or Infections (HSV, Mycoplasma)

EM Minor
– target lesions + mild/ no mucosal involvement

EM Major
– target lesions + 1 or more mucosal surfaces involved

Question 15

Describe in detail the skin lesions seen in SJS / TENs [4]

Answer 15

• Erythematous or purpuric macules
• Diffuse erythema
• Targetoid/ atypical target lesions
• Flaccid blisters

Question 16

What is a classic differentiating feature between pemphigoid and pemphigus? [2]

Answer 16

Bullous pemphigoid:
- mouth is usually spared
- blisters are more tense

Pemphigus vulgaris:
- Mouth commonly involved
- blisters commonly burst

Question 17

Complications associated with BP? [4]

Answer 17

Secondary infections:
* Staphylococcus aureus and Pseudomonas aeruginosa are the most common organisms
* risk of sepsis is significant due to disrupted skin integrity

Side effects from treatment:
- significant corticosteroid use: osteoporosis, diabetes mellitus, hypertension, glaucoma or cataracts

Elderly-related complications::
- Cognitive impairment has been linked with bullous pemphigoid

Increased risk of cardiovascular disease and stroke

Question 18

PV can be a pareneoplastic disease of which cancers? [2]

Answer 18

Lymphomas
Castleman disease

Question 19

Dapsone can be used to treat dermatitis herpetiformis.

Name some side effects of using as treatment [2]

Answer 19

hemolytic anaemia and methemoglobinemia

• regular monitoring of complete blood counts and methemoglobin levels.

Question 20

Patients with dermatitis herpetiformis have an increased risk of developing [], a rare but aggressive form of non-Hodgkin lymphoma.

Answer 20

Patients with dermatitis herpetiformis have an increased risk of developing Enteropathy-associated T-cell lymphoma (EATL), a rare but aggressive form of non-Hodgkin lymphoma.

Question 21

Explain some complications of erythroderma

Answer 21

Secondary infection
Acute renal failure
- water loss from skin; immune deposits in kidney

High output cardiac failure

Question 22

Describe the clinical presentation of eczema herpticum [6]

Answer 22

The skin lesions of eczema herpeticum typically present as painful clusters of blisters, fluid-filled elevations of the skin

Areas of rapidly worsening, painful eczema

The blisters appear widely over the body but are most common on the face, neck, and trunk.

Older blisters that have burst and dried commonly form “punched out” erosions, which are circular breaks in the continuity of the skin that may bleed or produce pus.

Possible fever, lethargy, lymphadenopathy or distress

Question 23

What is meant by ‘eczema herpeticum incognito’? [1]

Answer 23

presentation of EH that is easily mistaken for impetigo and most often seen in patients with severe AD and recurrent EH

Question 24

What is the name for when HSV can spread to the eye? [1]

What is the management? [1]

Answer 24

Rarely, HSV may spread to the eye resulting in herpes keratitis

Ganciclovir ointment five times daily (3 hourly) for 7-10 days

Question 25

A patient takes penicillin for an infection.

They come out in targetoid lesions.

What type of hypersensitivty reaction is this?

Type 1
Type 2
Type 3
Type 4

Answer 25

Type 1
Type 2
Type 3
Type 4

EM is considered a cell-mediated (type IV) hypersensitivity reaction, which is an abnormal cell-mediated reaction initiated by T cells.

The exact mechanism leading to EM is incompletely understood, but it appears to be an abnormal immune reaction to a drug metabolite or viral antigen that becomes expressed by keratinocytes within the skin

Question 26

What is the management for EM? [3]

Answer 26

Management

• EM typically develops over 3-5 days and improves over 2 weeks. Some patients may get persistent or recurrent episodes.
• Stop the drug
• Treat the underlying infection
• Treat with a week of oral prednisolone if severe mucosal pain/ difficulty eating

Question 27

Describe what is meant by SJS [1]

Describe the presentation of SJS [3]

Answer 27

Stevens-Johnson syndrome is a severe systemic reaction affecting the skin and mucosa that is almost always caused by a drug reaction.

Presentation:
* Patients usually start with non-specific symptoms of fever, cough, sore throat, sore mouth, sore eyes and itchy skin.
* They then develop a purple or red rash that spreads across the skin and starts to blister.
* Nikolsky sign is positive in erythematous areas - blisters and erosions appear when the skin is rubbed gently

NB: Nikolsky sign = where very gentle rubbing of the skin causes it to peel away

Question 28

Which drugs cause SJS? [7]
Which infection can also can? [1]

Answer 28

SPANLOC
* Sulphonamide
* Penicillin
* Phenytoin
* Allopurinol
* NSAIDS
* Lamotrigine
* OCP
* Carbamazepine

Most commonly caused by drugs. Less commonly infection eg Mycoplasma

Question 29

How do you dx SJS / TEN? [1]
What score is used for to classifiy the severity of SJS / TEN? [1]

Answer 29

Dx:
- skin biopsy

Severity:
- SCORTEN

sum of five points or more indicates a mortality risk of over 90%

Question 30

Pathophysiology of staphylococcal scalded skin syndrome (SSSS)? [1]

Answer 30

staphylococcus aureus bacteria that produces epidermolytic toxins. These toxins are protease enzymes that break down the proteins that hold skin cells together

When a skin infection occurs and these toxins are produced, the skin is damaged and breaks down.

This condition usually affects children under 5 years. Older children and adults have usually developed immunity to the epidermolytic toxins.

Question 31

Clinical presentation of SSSS? [5]

Answer 31

Fever:
- High fever (>38.9°C)

Rash:
- A diffuse, blanching erythroderma resembling sunburn usually appears early in the disease course.
- Desquamation, particularly on the palms and soles, typically occurs one to two weeks after the onset of illness

Myalgias and arthralgias are frequently reported;

Hypotension:
- Hypotension or shock may be present, often manifesting as systolic blood pressure less than 90 mmHg.

Question 32

Management for SSSS? [1]

Answer 32

• Admit
• Fluids
• IV flucloxacillin and clindamycin Clindamycin suppresses toxin production, while flucloxacillin targets the bacterial cell wall.
• If methicillin-resistant Staphylococcus aureus (MRSA) is suspected, vancomycin or daptomycin can replace flucloxacillin.

Question 33

What are the four types / causes of necrotising fasciitis? [4]

Answer 33

Type 1 – Polymicrobial (anaerobes + aerobes)
Type 2 – Group A beta-haemolytic streptococci
Type 3 – Clostridium perfringens; also associated with Vibrio species infection from seafood ingestion or water contamination of wounds.
Type 4 - Fungal infection

Question 34

Answer 34

Co-amoxiclav

Question 36

Tx for athletes foot? [3]

Answer 36

Clinical knowledge summaries recommend a topical imidazole, undecenoate, or terbinafine first-line

Question 37

Dx? [1]
Risk factor for..? [1]

Answer 37

Erythema ab igne

If the cause is not treated then patients may go on to develop squamous cell skin cancer.

Question 38

What are the features of erythema multiforme? [3]

Answer 38

Features
* 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

Question 39

How do you dx erythrasma? [1]

What is the treatment? [1]

Answer 39

Examination with Wood’s light reveals a coral-red fluorescence.

Topical miconazole or antibacterial are usually effective. Oral erythromycin may be used for more extensive infection

Question 40

What is meant by erythrasma? [1]

Answer 40

Erythrasma is a generally asymptomatic, flat, slightly scaly, pink or brown rash usually found in the groin or axillae.

It is caused by an overgrowth of the diphtheroid Corynebacterium minutissimum

Looks the same as acanthosis nigricans WITHOUT thickening/velvet like texture of the skin

Question 41

Fungal nail infections:

Causative organisms:
- dermatophytes account for around 90% of cases mainly []
- yeasts account for around 5-10% of cases
e.g. []

Answer 41

Causative organisms
dermatophytes account for around 90% of cases mainly Trichophyton rubrum

yeasts account for around 5-10% of cases e.g. Candida

Question 42

Investigation and mangement for fungal nail infections?

Answer 42

Investigation:
- nail clippings +/- scrapings of the affected nail for microscopy and culture
- should be done for all patients if antifungal treatment is being considered

Mangement:
- None if asymptomatic and unbothered
- if limited involvement (≤50% nail affected, ≤ 2 nails affected, more superficial white onychomycosis): topical treatment with amorolfine 5% nail lacquer; 6 months for fingernails and 9 - 12 months for toenails
- extensive: oral terbinafine is currently recommended first-line; 6 weeks - 3 months therapy is needed for fingernail infections whilst toenails should be treated for 3 - 6 months

Question 43

Which drugs are used for fungal nail infection, for both fingernails and nails, if:

• Limited involvement
• Extensive involvement
• Extensive involvement due to Candida infection

Answer 43

Limited involvement: - Topical treatment with amorolfine 5% nail lacquer
- Fingernails: 6 months
- Toe nails: 9-12 months

Extensive involvement - : oral terbinafin
- Fingernails: 6 weeks-3 months
- Toe nails: 3-6 months

Candida:
- oral itraconazole is recommended first-line;
- ‘pulsed’ weekly therapy is recommended

Question 44

Which four factors are in the criteria for hereditary haemorrhagic telangiectasia? [4]

Answer 44

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

NB only 3 are needed for a definite diagnosis; 2 is a possible diagnosis

Question 45

Describe what is meant by Hidradenitis suppurativa

Answer 45

Hidradenitis suppurativa
* Chronic, painful, inflammatory skin disorder.
* It is characterized by the development of inflammatory nodules, pustules, sinus tracts, and scars in intertriginous areas
* The axilla is the most common site
* Coalescence of nodules can result in plaques, sinus tracts and ‘rope-like’ scarring.

Question 46

Treatment of acute and chronic Hidradenitis suppurativa?

Answer 46

Acute flares:
- can be treated with steroids (intra-lesional or oral) or flucloxacillin.
- Surgical incision and drainage may be needed in some cases.

Long-term disease:
- can be treated with topical (clindamycin) or oral (lymecycline or clindamycin and rifampicin) antibiotics.

Question 47

Hyperhidrosis describes the excessive production of sweat.

What are 4 managment options? [4]

Answer 47

1. topical aluminium chloride preparations are first-line. Main side effect is skin irritation
2. iontophoresis: particularly useful for patients with palmar, plantar and axillary hyperhidrosis
3. botulinum toxin: currently licensed for axillary symptoms
4. surgery: e.g. Endoscopic transthoracic sympathectomy. Patients should be made aware of the risk of compensatory sweating

Question 48

What is the treatment algorithm for impetigo? [3]

Answer 48

Tx:
- Hydrogen peroxide 1% cream for ‘people who are not systemically unwell or at a high risk of complications’
- topical antibiotic creams: topical fusidic acid; topical mupirocin should be used if fusidic acid resistance is suspected
- Extensive disease: oral flucloxacillin; oral erythromycin if penicillin-allergic

Question 49

How do you treat keloid scars? [2]

Answer 49

Early keloids:
- triamcinolone

Excision is sometimes used (but can risk further keloid scarring)

Question 50

Describe what is meant by a leukoplakia [1]

How can you distinguish it from candidiasis and lichen planus? [1]

What is there a risk of transformation to? [1]

Answer 50

Leukoplakia
- is a premalignant condition which presents as white, hard spots on the mucous membranes of the mouth.
- Differentiae from candiasis and lichen planus if they can be ‘rubbed off’
- Need a biopsy to exclude squamous cell carcinoma as this can transform in about 1% patients

Question 51

Dx? [1]

Answer 51

Lichen planus - pruritic eruption on the shins

Skin disorder of unknown aetiology, most probably being immune-mediated.

Question 52

What are the 6Ps of LP? [6]

Answer 52

Pruritic
Purple
Polygonal
Planar
Papules
Plaques

Question 53

Management of LP? [2]

Answer 53

potent topical steroids are the mainstay of treatment
benzydamine mouthwash or spray is recommended for oral lichen planus

Question 54

Describe what is meany by lichen sclerosus [1]

What are the characteristic features? [3]

Answer 54

It is an inflammatory condition that usually affects the genitalia and is more common in elderly females.

Lichen sclerosus leads to atrophy of the epidermis with white plaques forming.

Features:
* white patches that may scar
* itch is prominent
* may result in pain during intercourse or urination

Question 55

How do you treat lichen sclerosus? [2]

Why do you follow up patients? [1]

Answer 55

Treatment:
* topical steroids and emollients

Follow up due to risk of vulval cancer

Question 56

What is mycosis fungoides? [1]

Answer 56

Mycosis fungoides is a rare form of T-cell lymphoma that affects the skin.

Question 57

How do you differentiate mycosis fungoides from eczema and psoriasis?

Answer 57

lesions tend to be of different colours in contrast to eczema/psoriasis where there is greater homogenicity

Question 58

This patient is suffering from dermatitis due a deficiency in a vitamin - which one? [1]

Answer 58

Pellegra - B3 deficiency
The classical features are the 3 D’s - dermatitis, diarrhoea and dementia.

Dermatitis (brown scaly rash on sun-exposed sites - termed Casal’s necklace if around neck)

Question 59

What is meant by Periorificial dermatitis? [1]

Management? [2]

Answer 59

A condition typically seen in women aged 20-45 years old. Topical corticosteroids, and to a lesser extent, inhaled corticosteroids are often implicated in the development of the condition.

Management:
* steroids may worsen symptoms
* should be treated with topical or oral antibiotics