Inflammatory skin Diseases 2 Flashcards
What is impetigo?
A superficial epidermal skin condition.
What is bacterial folliculitis/carbuncles?
Infection of hair follicles and sebaceous glands
What is cellulitis?
Infection
What are the predisposing factors of impetigo?
Minor trauma
Nasal carriage of staph
School and other institutions of close contact with other people
What causes impetigo most commonly?
Staph aureus (especially in bullous subtype) but it can also be caused by streptococcus.
What causes staphylococcal scalded skin?
The exfoliative toxins produced by staphylococcus
What are the types of impetigo?
Common impetigo (school sores, thin walled vesicles or pustules that rupture to form a thick golden crust, can be solitary or clustered)
Bullous impetigo (erosions and flaccid bullae, caused by an exotoxin which results in keratinocytes falling apart and blister formation)
What does histology look like with impetigo?
Subcorneal collection of neutrophils
Can see more neutrophils migrating upwards through the epidermis
Surface crust of serum and dying neutrophils
May see bacterial colonies
Which part of the hair follicle is affected most commonly by folliculitis?
Superficial part of the hair follicle (infundibulum)
What kinds of infection cause superficial folliculitis?
Can be bacterial (staph)
Can be fungal or viral
What is characteristic histopathology of superficial folliculitis?
Neutrophils in infundibulum
What is pseudofolliculitis?
Inflammation of follicles caused by trauma and other non-infectious causes (eg shaving and waxing or a drug reaction)
What is a furuncle?
A deep infectious inflammatory process within pilosebaceous unit. It is often caused by staphylococcus aureus
What does a furuncle look like?
It begins as a painful papule with surrounding erythema and swelling, center becomes soft, yellow and may discharge pus
What is a carbuncle?
Coalescence of several furuncles
What are the histological features of furuncles?
Deep dermal abscess centered around a hair follicle with lots of neutrophils.
Surrounding inflammation bay extend to deeper tissues
Surface often shows a crust of serum and dying neutrophils
What are eryspiles/cellulitis?
An acute inflammatory process within the dermis which is usually caused by streptococcus pyogenes
What do erysipelas/cellulitis look like?
Oedematous, tender, hot, well demarcated red plaques. As well as expanding area of erythema.
Most commonly affects face, feet, hands, and lower limbs