Dermatology - Common Rashes Flashcards
Cause of meningococcal rash?
Neisseria meningitidis
Appearance of meningococcal rash?
Non-blanching purpuric or petechial rash. All children presenting with this assumed to have meningococcus until proven otherwise.
Other symptoms that accompany a meningococcal rash?
pyrexia, malaise, meningitis (20-30%)
Management of a meningococcal rash?
Immediate admission to hospital, resuscitation and administration of broad-spectrum antibiotics
Complications of a meningococcal rash?
septicaemia, meningitis
What is SJS/TEN?
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare, acute, and potentially fatal skin reactions that cause sheet-like skin detachment and mucosal loss.
Causes of SJS/TEN?
Drugs (most common), chemicals (burns), infections, systemic illnesses
Appearance of lesions in SJS/TEN?
Widespread blisters/bullae over erythematous/macular/haemorrhagic skin.
Can also have haemorrhagic erosions on mucus membranes.
How do lesions in SJS/TEN progress?
Blisters start on the face before spreading to other areas
Associated symptoms in SJS/TEN?
fever, arthralgia, myalgia, conjunctivitis, pneumonitis
Management of SJS/TEN?
supportive (hydration/maintain airway), identify and remove causative agent, dermatology and critical care input
What is impetigo?
Impetigo is a superficial bacterial infection affecting the skin, most commonly in young children.
Cause of impetigo?
Staphylococcal aureus or streptococcal skin infection
Appearance of skin lesions in impetigo?
erythematous macules (may progress to be vesicular/bullous) on face, neck or hands
Epidemiology of impetigo?
infants and young children
Management of impetigo?
Topical (fusidic acid, mupirocin) or systemic (flucloxacillin or clarithromycin)
What is Kawasaki disease?
An acute systemic vasculitis that affects young children.
Cause of Kawasaki disease?
autoimmune-mediated (medium-sized blood vessel vasculitis)
Symptoms seen in Kawasaki disease?
- fever > 5 days
- conjunctivitis
- polymorphous exanthem
- fissuring of lips
- strawberry tongue
- diffuse erythema of oral and pharyngeal mucosa
- periungual desquamation of fingers and toes
- erythema of palms and soles
Investigations in Kawasaki disease?
- echocardiography (needs follow up 6 weeks later)
- inflammatory markers (ESR and CRP)
- alpha-1 antitrypsin
Management of Kawasaki disease?
- high dose intravenous immunoglobulin
- aspirin
What is Staphylococcal scalded skin syndrome?
a blistering skin disease caused by the exfoliate staphylococcal toxin.
Cause of SSSS?
exfoliative staphylococcal toxin
Appearance of SSSS?
blistering initially, then desquamation affecting flexural areas, buttocks, hands, or feet
Epidemiology of SSSS?
typically occurs in children under three years old
Associated symptoms in SSSS?
- fever
- irritability
- diffuse blanching erythema around the mouth
- desquamation as above
- positive Nikolsky’s sign (the epidermal layer easily sloughs off when pressure is applied)
Management of SSSS?
hospital admission, supportive care, analgesia and intravenous antibiotics (flucloxacillin is first-line)
What is the first line Abx in SSSS?
IV flucloxacillin
What is eczema herpeticum?
Eczema herpeticum is a complication of atopic eczema that occurs with infection of the herpes simplex virus (HSV).
Cause of eczema herpeticum?
type I HSV co-infection with active atopic eczema
Management of eczema herpeticum?
- oral acyclovir
- systemic antibiotics for secondary bacterial infection
What is erythema nodosum?
Red or violet subcutaneous nodules located pretibially
Causes of eythema nodosum?
- streptococcal pharyngitis
- idiopathic
- sarcoidosis
- primary tuberculosis
- inflammatory bowel disease
- drug reactions
What is erythema multiforme?
Erythema multiforme (EM) is a type IV hypersensitivity reaction that presents with a skin rash.
What is erythema multiforme typically triggered by?
It is typically triggered by an infection (most commonly herpes simplex virus), however, it can also develop secondary drug reactions.
What age group does erythema multiforme typically affect?
20-40
Causes of erythema multiforme?
HSV (90%), mycoplasma pneumonia, medications, autoimmune disease, sarcoidosis
Appearance of lesions in erythema multiforme?
Target-like lesions on the skin. Progresses to erosions of bullae which can involve oral, genital or mucosal areas.
Management of erythema multiforme?
Usually self-limiting, aciclovir is used to treat HSV infections
Oral antihistamines and corticosteroids can be used to reduce pruritus.
What is measles?
Measles is an infectious disease caused by a morbillivirus of the paramyxovirus family.
Appearance of measles rash?
maculopapular rash lasts 6-8 days
Associated symptoms of measles?
fever, coryza, cough, non-purulent conjunctivitis, Koplik spots
Epidemiology of measles?
young children with a seasonal peak in late winter/spring
Prevention of measles?
MMR vaccine at 18 months
Associated symptoms in glandular fever?
fever, fatigue, sore throat, lymphadenopathy
Why should you not give penicillin to a patient with EBV?
A maculopapular rash can occur due to being treated with penicillin whilst infected with EBV
What pathogen causes chickenpox?
VZV
Appearance of skin lesions in chickenpox?
starts on head and trunk, then spreads throughout the body. Red macules -> papules -> pustule-> crusting
What is scabies?
Scabies is a highly contagious skin infestation caused by a parasitic mite. It is spread by close contact and is more common among disadvantaged populations.
Cause of scabies?
an infestation of the skin by mite Sarcoptes scabiei resulting in a pruritic eruption
Appearance of lesions in scabies
mall, erythematous papule with haemorrhagic crusts on fingers, elbows, axillary folds, thighs, genitalia, feet
management of scabies?
hygiene advice, topical permethrin, oral ivermectin
What is tinea corporis?
Tinea corporis (also called ringworm) is a dermatophyte (fungal) infection of the body.
Cause of tinea corporis?
Trichophyton tubrum, Microsporum canis, Epidermophyton
Appearance of lesions in tinea corporis?
pruritic, circular, erythematous scaly patch spreading centrifugally. Central clearing is seen
Management of tinea corporis?
daily application of topical antifungals
Systemic therapy indicated in patients with failed topical therapy (terbinafine, fluconazole or itraconazole).
Cause of molluscum contagiosum?
Poxvirus
