Dermatology emergencies

Question 1

Acute urticaria clinical features

Answer 1

Pale, pink raised skin

Pruritic

Question 2

Acute urticaria mx

Answer 2

Non-sedating antihistamines (eg. cetirizine) are first line

• continue these for up to 6 weeks following an episode of acute urticaria

Sedating antihistamine (eg. chlorphenamine) may be considered for night-time use for troublesome sleep symptoms

Prednisolone - severe or resistant episodes

Question 3

Uncomplicated drug reactions

Answer 3

Drug induced exanthem (morbilliform drug eruption)

Fixed drug eruption

Type 1 hypersensitivity reactions

Lichenoid drug eruptions

Phototoxic reactions

Question 4

Severe cutaneous adverse reactions (SCAR)

Answer 4

DRESS

AGEP

SJS-TENS

Question 5

DRESS

Answer 5

Drug reaction with eosinophilia and systemic symptoms (also known as drug induced hypersensitivity syndrome)

Presents with a morbilliform rash, with systemic symptoms eg. fever, potential multi-organ dysfunctionn, haematological abnormalities, neurological, endocrine or GI manifestations and raised eosinophils

Facial oedema is characteristic

Mx - stop offending agent, supportive treatment due to risk of dehydration, oral prednisolone, IVIG/plasma exchange if life threatening

Question 6

AGEP

Answer 6

Acute generalised exanthematous pustulosis

Onset is sudden, within 24 hours of drug being commenced → patient febrile with an eruption of sterile pustules

Patient is unwell & rash is itchy & painful

Mx - stop offending agent, use of topical/systemic steroids with best supportive care

Question 7

SJS-TENS

Answer 7

Steven Johnsons Syndrome and Toxic Epidermal Necrolysis are blistering, desquamating delayed T-cell reactions to drugs, with mucous membrane involvement

Takes many weeks for the reaction to develop after initial drug exposure

SJS = < 10% epidermal detachment, 10-30% = SJS-TENS overlap, > 30% = TENS

Typically carbamazepine, phenytoin & abacavir

Question 8

SJS-TENS clinical features

Answer 8

Prodrome - viral symptoms

Followed by erythroderma, atypical target lesions & flaccid blisters

Multi-organ dysfunction & death can occur

Nikolsky’s sign is positive

Question 9

SJS-TENS mx

Answer 9

Offending drug should be stopped

Nursing in a high acuity setting with burns centre management → use of special dressings & paying close attention to fluid loss and infection risk is necessary

Analgesia, support with hydration & nutrition, close monitoring

Ophthalmology input may be required due to eye involvement

Prognosis - SCORTEN & ABCD-10 criteria

Question 10

Eczema herpeticum

Answer 10

Potentially serious widespread HSV infection, with typically affects people with atopic dermatitis or eczema

Question 11

Eczema herpeticum clinical features

Answer 11

Appear 5-12 days after contact with an infected individual

Areas of rapidly worsening, painful eczema

Vesicular rash

Punched-out erosions

Possible fever, lethargy, lymphadenopathy or distress

Rarely → can spread to the eye (herpes keratitis) → ophthalmological referral

Question 12

Eczema herpeticum ix

Answer 12

Viral infection can be confirmed by viral swabs → PCR, viral culture, direct fluorescent antibody stain

Herpetic keratitis → staining with fluorescein - stained dendritic ulcer is diagnostic

Question 13

Eczema herpeticum mx

Answer 13

Prompt treatment with antiviral meds - oral aciclovir 5 times daily for 10-14 days (if vomiting → IV)

Ocular involvement:

• ganciclovir ointment five times daily for 7-10 days
• corneal transplant may be indicated where vision significantly affected by scarring

Question 14

Eczema herpeticum complications

Answer 14

Secondary infection

Scarring

Herpetic keratitis

Organ failure & dissemination

Question 15

Necrotising fasciitis

Answer 15

Life-threatening rapidly-progressing infection that spreads along the fascial planes & subcutaneous tissue

Surgical emergency

Fournier’s gangrene = specifically a necrotising infection of the perineum

Question 16

Necrotising fasciitis types

Answer 16

Type I - polymicrobial infection, primarily caused by a mixture of anaerobes & aerobes; it is the more common of the two subtypes, especially in elderly or co-morbid patients

Type II - monomicrobial infection, primarily caused by strep pyogenes & is more common in healthy individuals with a history of trauma

Question 17

Gas gangrene

Answer 17

Form of necrotising fasciitis caused by clostridium species, resulting in gas being produced by the bacteria within the tissue

Extensive tissue damage, alongside large volumes of gas within the tissue

Tissue crepitus is often present on light palpation of the affected area, management same as any nec fasc

Question 18

Necrotising fasciitis risk factors

Answer 18

Diabetes mellitus

CKD

Alcohol excess

Advanced age or frailty

Malnutrition

Metastatic cancer

Immunocompromised

Question 19

Necrotising fasciitis clinical features

Answer 19

Rapid progression

Severe pain, out of keeping with the overt clinical signs

O/E - skin erythema, oedema, signs of skin ischaemia, skin crepitus, vesicles/bullae, obvious skin necrosis

Question 20

Necrotising fasciitis ix

Answer 20

Blood tests - FBC, CRP, U&Es, LFTs, clotting, glucose

Blood gas - raised lactate +/- metabolic acidosis

Blood cultures

Question 21

Necrotising fasciitis mx

Answer 21

Urgent broad spectrum antibiotics

Resuscitation IV fluids

Urgent surgical debridement, with a relook in 24-48 hours

Transfer to ITU

Reconstructive surgery might be needed after initial debridement → plastic surgery services

Question 22

Staphylococcal scalded skin syndrome

Answer 22

Severe desquamating rash that primarily affects infants

Question 23

Staphylococcal scalded skin syndrome pathophysiology

Answer 23

Occurs due to the production of an exfoliative exotoxin by staph aureus

The exotoxin splits the epidermis in the granular cell layer, specifically targeting desmoglein 1

Question 24

Staphylococcal scalded skin syndrome clinical features

Answer 24

Superficial fluid-filled blisters, often leading to erythroderma (erythema affecting over 90% of the body surface)

Desquamation (peeling of the epidermis) occurs, with a positive Nikolsky sign

Perioral crusting or fissuring is frequently observed, with oral mucosa usually remaining unaffected (contrasts with TEN)

Fever and irritability due to underlying infection

Question 25

Staphylococcal scalded skin syndrome mx

Answer 25

IV antibiotics - clindamycin

Fluid replacement

Pain management

Careful wound care to prevent secondary infections