Dermatology

Question 1

What is Pityriasis Rosea?

Answer 1

Pityriasis rosea describes an acute, self-limiting rash which tends to affect young adults.

Herald patch followed 1-2 weeks later by multiple erythematous, slightly raised oval lesions with a fine scale confined to the outer aspects of the lesions.

May 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.

Self-limiting, resolves after around 6 weeks.

Question 2

Mx for Actinic Keratosis?

Answer 2

AK is a common premalignant skin condition.
- Small, crusty or scaly, lesions
- May be pink, red, brown or the same colour as the skin
- Typically on sun-exposed areas e.g. temples of head

1. Sun avoidance, sun cream
2. Fluorouracil cream: typically a 2 to 3 week course.
3. Topical diclofenac: may be used for mild AKs. Moderate efficacy but much fewer side-effects
4. Topical imiquimod: trials have shown good efficacy
5. cryotherapy
6. curettage and cautery

Question 3

Feature of BCC?

Answer 3

BCC lesions are also known as rodent ulcers and are characterised by slow-growth and local invasion. Metastases are extremely rare. BCC is the most common type of cancer in the Western world.

1. Sun-exposed sites, especially the head and neck account for the majority of lesions
   - initially a pearly, flesh-coloured papule with telangiectasia
   - may later ulcerate leaving a central ‘crater’

• Surgical removal
• Curettage
• Cryotherapy
• Topical cream: imiquimod, fluorouracil
• Radiotherapy

Question 4

Types of Psoriasis?

Answer 4

1. Plaque psoriasis: the most common sub-type resulting in the typical well-demarcated red, scaly patches affecting the extensor surfaces, sacrum and scalp.
2. Flexural psoriasis: in contrast to plaque psoriasis the skin is smooth.
3. Guttate psoriasis: transient psoriatic rash frequently triggered by a streptococcal infection. Multiple red, teardrop lesions appear on the body.
4. Pustular psoriasis: commonly occurs on the palms and soles.

Question 5

Pompholyx?

Answer 5

AKA Dyshidrotic eczema, primarily affects hands and feet causing itchy vesicles.

Pompholyx is a type of eczema which affects both the hands (cheiropompholyx) and the feet (pedopompholyx). It is also known as dyshidrotic eczema.

Pompholyx eczema may be precipitated by humidity (e.g. sweating) and high temperatures.

Features:
- small blisters on the palms and soles
- pruritic
- often intensely itchy
- sometimes burning sensation
- once blisters burst skin may become dry and crack

Management
cool compresses
emollients
topical steroids

Question 6

Polymorphic eruption of pregnancy?

Answer 6

A benign dermatological condition that occurs in late pregnancy. It typically presents with intensely itchy, polymorphic lesions including erythematous papules, vesicles or plaques. The rash often starts on the abdomen, particularly within stretch marks (striae), and can spread to the thighs and buttocks but rarely involves the face or mucous membranes.

Management depends on severity: emollients, mild potency topical steroids and oral steroids may be used.

USUALLY SPARES UMBILICUS.

Question 7

Pemphigoid Gestationis?

Answer 7

• 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.

-Oral corticosteroids are usually required.

Question 8

Features of HHT?

Answer 8

AKA Osler-Weber-Rendu syndrome, HHT is an autosomal dominant condition characterised by multiple telangiectasia over the skin and mucous membranes.

1. Epistaxis : spontaneous, recurrent nosebleeds.
2. Telangiectases: multiple at characteristic sites (lips, oral cavity, fingers, nose).
3. Visceral lesions: for example gastrointestinal telangiectasia, pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM.
4. Family history: a first-degree relative with HHT

Question 9

Lichen Scelrosus?

Answer 9

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

• White patches that may scar
• Itch is prominent
• May result in pain during intercourse or urination

Management: Topical steroids and emollients

Question 10

Seborrhoeic keratoses?

Answer 10

Seborrhoeic keratoses are benign epidermal skin lesions seen in older people.

• Large variation in colour from flesh to light-brown to black.
• Have a ‘stuck-on’ appearance
• Keratotic plugs may be seen on the surface.

Mx:
Reassurance about the benign nature of the lesion is an option.
Options for removal include curettage, cryosurgery and shave biopsy.

Question 11

Causes of Erythema Nodosum?

Answer 11

• Inflammation of subcutaneous fat
  typically causes tender, erythematous, nodular lesions.
• Usually occurs over shins, may also occur elsewhere (e.g. forearms, thighs).
• Usually resolves within 6 weeks
  lesions heal without scarring.

Causes:
1. Infection
- streptococci
- tuberculosis
- brucellosis

2. systemic disease
   - sarcoidosis
   - inflammatory bowel disease
   - Behcet’s
3. Malignancy/lymphoma
4. Drugs
   - penicillins
   - sulphonamides
   - COCP
5. Pregnancy

Question 12

Pemphigus vulgaris features?

Answer 12

Pemphigus vulgaris is an autoimmune disease caused by antibodies directed against desmoglein 3, a cadherin-type epithelial cell adhesion molecule.

Mucosal ulceration is common and often the presenting symptom. Oral involvement is seen in 50-70% of patients.

• Skin blistering: FLACCID, easily ruptured vesicles and bullae. Lesions are typically painful but not itchy. These may develop months after the initial mucosal symptoms.

Mx:
Steroids are first-line
Immunosuppressants

Question 13

Guttate Psoriasis?

Answer 13

Guttate psoriasis is more common in children and adolescents. It may be precipitated by a streptococcal infection 2-4 weeks prior to the lesions appearing.

• Tear drop papules on the trunk and limbs.
• pink, scaly patches or plaques of psoriasis
• Tends to be acute onset over days

Mx:
- Most cases resolve spontaneously within 2-3 months
- Topical agents as per psoriasis
UVB phototherapy
-Tonsillectomy may be necessary with recurrent episodes

Question 14

Necrobiosis lipoidica?

Answer 14

• Shiny, painless areas of yellow/red skin typically on the shin of DIABETICS.
• often associated with telangiectasia

Question 15

Erythema Multiforme trigger?

Answer 15

Erythema multiforme is a hypersensitivity reaction that is most commonly triggered by infections.

1. Target lesions
2. Initially seen on the back of the hands / feet before spreading to the torso
3. upper limbs are more commonly affected than the lower limbs
4. pruritus is occasionally seen and is usually mild
5. Viruses: herpes simplex virus (the most common cause), Orf*
6. idiopathic
7. bacteria: Mycoplasma, Streptococcus
8. Drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
   connective tissue disease e.g. Systemic lupus erythematosus
9. Sarcoidosis
10. Malignancy

Question 16

Mx for scabies?

Answer 16

1. Permethrin 5% is first-line
2. Malathion 0.5% is second-line
   pruritus persists for up to 4-6 weeks post eradication

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.

1. Apply the insecticide cream or liquid to cool, dry skin.
2. Pay close attention to areas between fingers and toes, under nails, armpit area, creases of the skin such as at the wrist and elbow
3. Allow to dry and leave on the skin for 8-12 hours for permethrin, or for 24 hours for malathion, before washing off
4. Reapply if insecticide is removed during the treatment period, e.g. If wash hands, change nappy, etc
5. Repeat treatment 7 days later

Question 17

Which medication is known to exacerbate plaque psoriasis?

Answer 17

Psoriasis may be exacerbated by a variety of causes. With respect to drugs, the most common suspects are lithium and BETA BLOCKERS. Other agents include antimalarials, ACE inhibitors and non-steroidal anti-inflammatories

Question 18

Mx for vitiligo?

Answer 18

• Loss of melanocytes and consequent depigmentation of the skin.

Associated conditions:
- Type 1 diabetes mellitus
- Addison’s disease
- Autoimmune thyroid disorders
- Pernicious anaemia
- Alopecia areata

Mx:
- Sunblock for affected areas of skin
- Topical corticosteroids may reverse the changes if applied early
- There may also be a role for topical tacrolimus and phototherapy.

Question 19

Features of zinc deficiency?

Answer 19

Zinc deficiency causes a characteristic skin rash (mainly affecting the intertriginous and perioral areas), alopecia, taste impairment, glucose intolerance, and diarrhoea.

1. Acrodermatitis: red, crusted lesions
2. Alopecia
3. Short stature
4. Hypogonadism
5. Hepatosplenomegaly
6. Geophagia (ingesting clay/soil)
7. Cognitive impairment

Question 20

Features of pyogenic granuloma?

Answer 20

Pyogenic granuloma is a relatively common benign skin lesion. The name is confusing as they are neither true granulomas nor pyogenic in nature.

• Most common sites are head/neck, upper trunk and hands. Lesions in the oral mucosa are common in pregnancy.
• Initially small red/brown spot
  rapidly progress within days to weeks forming raised, red/brown lesions which are often spherical in shape
• The lesions may bleed profusely or ulcerate. hey can develop rapidly over a few weeks and tend to bleed easily because they contain many blood vessels.

Question 21

Features of yellow nail syndrome?

Answer 21

Slowing of the nail growth leads to the characteristic thickened and discoloured nails seen in yellow nail syndrome.

Associations:
1. Congenital lymphoedema
2. Pleural effusions
3. Bronchiectasis
4. Chronic sinus infections

Question 22

Pyoderma Gangrenosum associated with which conditions?

Answer 22

Pyoderma gangrenosum is a rare, non-infectious, inflammatory disorder. It is an uncommon cause of very painful skin ulceration. It may affect any part of the skin, but the lower legs are the most common site.

Pyoderma gangrenosum is classified as a neutrophilic dermatosis. Neutrophilic dermatoses are skin conditions characterised by dense infiltration of neutrophils in the affected tissue and this is often seen on biopsy.

1. Idiopathic in 50%
2. IBD
3. RA, SLE
4. Myeloproliferative disorders
   lymphoma
   myeloid leukaemias
5. Monoclonal gammopathy (IgA)
6. ranulomatosis with polyangiitis
7. Primary biliary cirrhosis

• Typically on the lower limb, often at the site of a minor injury, this is known as pathergy
• Usually starts quite suddenly
  small pustule, red bump or blood-blister
• The skin then breaks down resulting in an ulcer which is often painful
  the edge of the ulcer is often described as purple, violaceous and undermined.
• The ulcer itself may be deep and necrotic
• Fever, myalgia

Mx:
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

Question 23

Cherry Haemangioma?

Answer 23

Cherry haemangiomas are benign skin lesions which contain an abnormal proliferation of capillaries. They are more common with advancing age and affect men and women equally.

Question 24

Management for Chronic plaque psoriasis?

Answer 24

Regular emollients may help to reduce scale loss and reduce pruritus.

1. Potent corticosteroid applied once daily plus vitamin D analogue applied once daily.
   - should be applied separately, one in the morning and the other in the evening.
   - for up to 4 weeks as initial treatment

second-line: if no improvement after 8 weeks then offer:
2. Vitamin D analogue twice daily

Third-line: if no improvement after 8-12 weeks then offer either:
3. A potent corticosteroid applied twice daily for up to 4 weeks or
a coal tar preparation applied once or twice daily.

• Short-acting dithranol can also be used

Question 25

Features of Rosacea?

Answer 25

• 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
• Sunlight may exacerbate symptoms

Symptoms also worsen with alcohol causing vasodilation.

Question 26

Mx for Rosacea?

Answer 26

predominant erythema/flushing:
1. Topical brimonidine gel may be considered for patients with predominant flushing but limited telangiectasia.

Brimonidine is a topical alpha-adrenergic agonist
this can be used on an ‘as required basis’ to temporarily reduce redness
it typically reduces redness within 30 minutes, reaching peak action at 3-6 hours, after which the redness returns to the baseline.

mild-to-moderate papules and/or pustules :
Topical ivermectin is first-line
- alternatives include: topical metronidazole or topical azelaic acid

Moderate-to-severe papules and/or pustules
Combination of topical ivermectin + oral doxycycline

Question 27

Features of Bowen’s disease?

Answer 27

Bowen’s disease is a type of precancerous dermatosis that is a precursor to squamous cell carcinoma. There is around a 5-10% chance of developing invasive skin cancer if left untreated.

Red, scaly patches
- often 10-15 mm in size
- slow-growing
- often occur on sun-exposed areas such as the head (e.g. temples) and neck, lower limbs

Mx:
- Topical 5-fluorouracil:
typically used twice daily for 4 weeks
often results in significant inflammation/erythema.

• Topical steroids are often given to control this
• cryotherapy
• excision

Question 28

Features of dermatitis herpetiformis?

Answer 28

Dermatitis herpetiformis is an autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.

• Itchy, vesicular skin lesions on the extensor surfaces (e.g. elbows, knees, buttocks)

Skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis.

Mx: GLuten free diet, Dapsone.

Question 29

How is Pellagra related to carcinoid syndrome?

Answer 29

In carcinoid syndrome, neuroendocrine tumours along the GI tract use tryptophan as the source for serotonin production, which limits the available tryptophan for niacin synthesis.

Pellagra may occur as a consequence of isoniazid therapy (isoniazid inhibits the conversion of tryptophan to niacin) and it is more common in alcoholics.

• Dermatitis (brown scaly rash on sun-exposed sites - termed Casal’s necklace if around neck).
• Diarrhoea
• Dementia, depression
• Death if not treated

Question 30

What is alopecia Areata?

Answer 30

Alopecia areata is a presumed autoimmune condition causing localised, well demarcated patches of hair loss. At the edge of the hair loss, there may be small, broken ‘exclamation mark’ hairs.

Question 31

Scalp psoriasis management?

Answer 31

NICE recommend the use of potent topical corticosteroids used once daily for 4 weeks
if no improvement after 4 weeks then either use a different formulation of the potent corticosteroid (for example, a shampoo or mousse) and/or a topical agents to remove adherent scale (for example, agents containing salicylic acid, emollients and oils) before application of the potent corticosteroid

Question 32

Skin biopsy of bullous pemphigoid?

Answer 32

• Itchy, TENSE blisters typically around flexures.
• The blisters usually heal without scarring.
• There is stereotypically no mucosal involvement (i.e. the mouth is spared)
  in reality around 10-50% of patients have a degree of mucosal involvement.

Skin biopsy:
Immunofluorescence shows IgG and C3 at the dermoepidermal junction.

Question 33

Mx for Lichen Planus?

Answer 33

• Itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms.
• Rash often polygonal in shape, with a ‘white-lines’ pattern on the surface (Wickham’s striae).
• Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma).
• Oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
• Nails: thinning of nail plate, longitudinal ridging

Management:
potent 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

Question 34

Side effect of Dapsone?

Answer 34

Dapsone is an antibacterial agent that can provide temporary symptomatic relief as a gluten-free diet is established. The main side effect is that of haemolytic anaemia - so regular full blood counts are essential. Other side effects include peripheral neuropathy and rarely agranulocytosis.

Question 35

Erythema ab igne?

Answer 35

Erythema ab igne is a skin disorder caused by over exposure to infrared radiation. Characteristic features include reticulated, erythematous patches with hyperpigmentation and telangiectasia. A typical history would be an elderly women who always sits next to an open fire.

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

Question 36

Mx for Tinea capitis?

Answer 36

Tinea capitis (scalp ringworm)
a cause of scarring alopecia mainly seen in children.

if untreated a raised, pustular, spongy/boggy mass called a kerion may form

diagnosis: lesions due to Microsporum canis green fluorescence under Wood’s lamp*. However the most useful investigation is scalp scrapings.

Mx:
1. Oral antifungals: terbinafine for Trichophyton tonsurans infections and griseofulvin for Microsporum infections.
Topical ketoconazole shampoo should be given for the first two weeks to reduce transmission

Question 37

Leser- Trelat sign?

Answer 37

lesions are common and are benign although the rapid development of large numbers of them is cause for concern. This is termed the Leser-Trelat sign and is most commonly associated with gastrointestinal adenocarcinomas and hepatic cancers.

Question 38

Leukoplakia features?

Answer 38

Leukoplakia is a premalignant condition which presents as white, hard spots on the mucous membranes of the mouth. It is 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.

Question 39

What is Mohs surgery?

Answer 39

Mohs surgery is a technique used to remove malignant lesions from cosmetically-sensitive areas such as the face. This is often used for basal cell carcinomas of the face

Question 40

Chondrodermatitis nodularis helicis?

Answer 40

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.

Mx:
- 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.

TENDER.

NON TENDER WOULD BE KERATIN HORN!

Question 41

What is a Keratoacanthoma?

Answer 41

Keratoacanthoma is a benign epithelial tumour. They are more common with advancing age and rare in young people.

Features:
- said to look like a volcano or crater
- initially a smooth dome-shaped papule
- rapidly grows to become a crater centrally-filled with keratin