Dermatology

Question 1

Difference between SJS + TEN

Answer 1

SJS < 10% BSA epidermal detachment

SJS/ TEN overlap 10-30% BSA

TEN > 30% BSA

Question 2

Definition of DRESS: drug reaction with eosinophilia and systemic symptoms

Answer 2

Drug induced syndrome of rash, fever, lymphadenopathy, haematologic abnormalities, hepatitis

Most often reported with anticonvulsants, NSAIDS + antibiotics. Usually weeks after commencement.

Associated with HHV6 + 7 reactivation

Lack of severe mucosal involvement distinguishes from SJS / TEN

Question 3

How do you confirm the diagnosis of HSP?

Answer 3

Skin biopsy which shows positive IgA antibodies on immunofluorescence

Question 4

Causes of palpable purpura

Answer 4

Vasculitis

Infection- meningococcaemia

Hypersensitivity- medication particularly antibiotics + NSAIDs

Immune mediated- lupus, dermatomyositis, Churg-Strauss / Wegner

Question 5

Differentiating features of HSV vs. varicella

Answer 5

Monomorphic

Lesions are all the same age of evolution

Lesions bunch together

Question 6

Describe pyogenic granuloma

Answer 6

Common skin growth presents as a shiny red mass

‘Granuloma telangiectaticum’ or ‘lobar capillary angioma’

Benign, cause discomfort and profuse bleeding

Question 7

Causes of lens dislocation

Answer 7

Most common is trauma

Superior dislocation- Marfan’s

Inferior dislocation
- Homocystinuria (fair hair + developmental delay)

Question 8

Clinical sign of optic atrophy

Answer 8

Macula is > 2.5 optic discs away from the optic disc!

Question 9

Causes of unilateral red eye

Answer 9

Foreign body
Herpes infection- dendritic ulcer (stain with fluoresin)
Glaucoma
Iritis
Conjunctivitis- only by exclusion

Question 10

The P’s of candidiasis

Answer 10

The P’s

• Paediatric (if <1yr okay)
• Penicillin use
• Pregnancy
• Pill use
• Parturition
• Prednisone use

If not ‘p’ associated then need to exclude serious pathology such as:

• Diabetes
• Immune suppression
• Malignancy
• Drugs

Question 11

Treatment of cradle cap ‘seborrheic dermatitis’

Answer 11

Cold pressed oil

1% hydrocortisone

Question 12

What cell will be seen on microscopy with erythema toxicum?

Answer 12

Eosinophils

Question 13

Involution of haemangioma % at 5 yrs + 9yrs

Answer 13

60% involution at 5yrs

95% involution at 9yrs

Question 14

What syndromes are associated with segmental haemangiomas?

Answer 14

PHACE
Posterior fossa abnormalities
Haemangiomas
Arterial anomalies
Cardiac + coarctation
Eye + endocrine
Sternal cleft, supra-umbilical raphae 

Sturge-Weber

Question 15

What virus is erythema multiforme MOST commonly associated with?

Answer 15

HSV

Question 16

What HLA is DRESS associated with?

Answer 16

HLA-A 3101

Question 17

What HLA is SJS associated with?

Answer 17

HLA-B1502

Question 18

What antibody is associated with pemphigus vulgaris + what is the most common site of ulcers?

Answer 18

Desmoglein III

Oral cavity

Question 19

What is Nikolsky’s sign?

Answer 19

Lateral pressure causes dislodgement of epidermis

Question 20

Characteristics of eczema herpeticum

Answer 20

The blisters are monomorphic, i.e. they all appear similar to each other.

They may be filled with clear yellow fluid or thick purulent material.

They are often blood-stained i.e., red, purple or black in colour.

New blisters have central dimples (umbilication).

They may weep or bleed.

Older blisters crust over and form sores (erosions).

Question 21

What cells + cytokines play a prominent role in eczema?

Answer 21

T-lymphocytes play a prominent role in eczema. T cells tend to be chronically stimulated and have increased cell turnover.

In eczema, the number of CD4+ cells is increased, and CD8+ cells are decreased in peripheral blood.

Eczema is also associated with a Th2 cytokine profile

Question 22

Characteristics of Sturge-Weber syndrome

Answer 22

Sporadic vascular disorder

Seizures
Trigeminal distribution of port wine stain
Unilateral weakness (usually opposite side to port wine lesion)
Retardation (developmental delay)
Glaucoma
Bupthalmos of the ipsilateral eye

NOT all children with a port-wine stain have SWS

Question 23

Biopsy features of;

Vasculitic lesions
SSSS
SJS
TEN

Answer 23

Vasculitic lesions
- Granular layer with a perivascular lymphocytic and neutrophilic infiltrate

SSSS
- Granular layer with no inflamm cell infiltrate

SJS
- Subepidermal layer with full thickness epidermal necrosis

TEN
- Subepidermal layer with intense perivascular and interstitial mononuclear cell infiltrate

Question 24

Phimosis vs. paraphimosis

Answer 24

Phimosis refers to the inability to retract the prepuce. At birth, phimosis is physiologic. Over time, the adhesions between the prepuce and glans lyse and the distal phimotic ring loosens. In 90% of uncircumcised males the prepuce becomes retractable by the age of 3 years.

Paraphimosis occurs when the foreskin is retracted past the coronal sulcus and the prepuce cannot be pulled back over the glans. Painful venous stasis in the retracted foreskin results. with oedema leading to severe pain and inability to reduce the foreskin . Treatment includes lubricating the foreskin and glans and then simultaneously compressing the glans and placing distal traction on the foreskin to try to push the phimotic ring past the coronal sulcus.

Question 25

Incontinetia pigmenti diagnostic criteria

Answer 25

Major criteria

• Typical neonatal vesicular rash with eosinophilia; (in most cases cutaneous manifestations are present at birth)
• Typical blaschkoid hyperpigmentation on the trunk, fading in adolescence; - Linear, atrophic hairless lesions.

Minor criteria

• Dental anomalies,
• Alopecia,
• Wooly hair
• Abnormal nails

Question 26

Risk of allergic disease / atopy

• 1 parent allergic
• 2 parents allergic
• > 2 first degree relatives allergic

Answer 26

The risk of allergic disease/atopy in a child approaches 50% when one parent in allergic and 66% when both parents are allergic. In families with more than two allergic first degree relatives, 67% of children had an allergic disease/atopy.

Question 27

Mechanism of action of pimecrolimus

Answer 27

Pimecrolimus is anti-inflammatory. It inhibits calcineurin thus blocking T cell proliferation and preventing release of inflammatory cytokines.
Adverse effects include:

Common: local irritation, burning sensation, itch, erythema, skin infections
Infrequent: local rash, aggravation of eczema, herpes simplex dermatitis, impetigo
Rare: alcohol intolerance (facial flushing, rash, burning sensation), allergy (eg urticaria, angioedema)
In contrast with topical steroids, pimecrolimus does not produce skin atrophy.

Question 28

What is pyoderma gangrenosum?

Answer 28

Inflammatory skin disease often (~50%) associated with underlying systemic disorders such as inflammatory bowel disease, arthritis, and lymphoproliferative disorders.

As an example, pyoderma gangrenosum occurs in up to 5% of patients with ulcerative colitis and 2% of those with Crohn’s disease. Among patients with inflammatory bowel disease, PG may parallel the activity of the bowel disease.

The eruption may begin as an isolated pustule or scattered lesions on the trunk or extremities. There is surrounding oedema and purplish induration with rapid progression into a large ulcer which heals ultimately with cribiform scars.

Question 29

What is neonatal pustulosis melanosis and what cell is involved?

Answer 29

Benign self-limiting rash

Present at birth or shortly after with pustular lesions, neonate is otherwise well

Pustules resolve spontaneously but may leave areas of hyperpigmentation

More common in dark skinned children

Microscopic examination reveals neutrophils with no associated organisms

Question 30

What cell is involved in erythema toxicum?

Answer 30

Eosinophils

Occurs in 50% of term babies

Question 31

Zinc deficiency risk factors + clinical presentation

Answer 31

Zinc deficiency occurs rarely in exclusively breast-fed infants (usually premature) whose mothers have a low level of zinc in their breast milk. The clinical presentation is similar to that of acrodermatitis enteropathica.

Zinc is an essential mineral i.e. needs to be obtained from the diet as cannot be synthesised in the body. One of the causes of zinc deficiency is excessive losses in intestinal illnesses as malabsorption occurs and diarrhoea results in excessive losses of zinc.

In this case the mother has extensive Crohns disease and so is likely to have zinc deficiency hence her breastmilk will have low levels of zinc. Cases of zinc deficiency during breast-feeding are accompanied by skin rashes or dermatitis which are the main symptoms, often in combination with failure to thrive, low serum zinc and irritability.

Numerous signs and symptoms have been associated with zinc depletion.
Mild zinc deficiency is associated with depressed immunity, impaired taste and smell, onset of night blindness, and decreased spermatogenesis.
Severe zinc deficiency is characterised by severely depressed immune function, frequent infections, bullous pustular dermatitis, diarrhea, and alopecia.
The skin changes are the most distinctive manifestations. These usually consist of dry scaly eczematous placques, often on the face and anogenital area; the lesions often resemble psoriasis.

Question 32

What is the other term for blueberry muffin spots?

Answer 32

Extramedullary erythropoiesis

Question 33

Causes of blueberry muffin spots

Answer 33

Tumours such as:
Congenital leukaemia cutis
Langherhans cell histiocytosis
Neuroblastoma
Congenital rhabdomyosarcoma

Blood disorders such as:
Haemolytic disease of the newborn – rhesus or ABO incompatibility
Hereditary spherocytosis
Twin-twin transfusion syndrome

Congenital infections such as:
Rubella
Toxoplasmosis
Cytomegalovirus
Herpes simplex
Coxsackie virus
Parvovirus
Epstein Barr virus
Syphilis