Dermatology Flashcards
What is cellulitis?
A spreading infection of the deep subcutaneous layer of the skin. It is the most common skin infection leading to admission to hospital
What preferential anatomical distribution does cellulitis demonstrate?
Cellulitis preferentially involves the lower limbs and extremities
What is erysipleas? What anatomical proclivity does it show?
Similar to cellulitis; it is an infection of the deep dermis and subcutaneous tissues and has a proclivity for involvement of the face
What are the most common bacterias causing cellulitis/erysipleas?
Streptococcus spp. most commonly
Rarely staphylococcus
What is the clinical presentation of cellulitis?
Tender erythematous patch with poorly demarcated borders, swelling, warmth and potentially a low grade fever
What is the clinical presentation of erysipleas?
Raised erythematous area with sharply demarcated borders, warmth, tenderness and potentially a low grade fever.
What is the major differential diagnosis to be ruled out in the case of suspected cellulitis of the lower limb?
Deep vein thrombosis
What is the antibiotic of choice for treatment of cellulitis/erysipleas?
Flucloxacillin (erythromycin if penicillin allergic)
If disease is diffuse then intravenous therapy for 3-5 days followed by at least two weeks of oral therapy
What is necrotising fasciitis?
A deep-seated infection of the subcutaneous tissue that results in fulminant and spreading destruction of the fascia and fat.
May initially spare the skin, leading to delayed diagnosis
What are the clinical features of necrotising fasciitis?
Spreading erythema and underlying crepitus with severe pain and system toxicity (disproportionate to skin findings)
Outline the difference between type 1 and type 2 necrotising fasciitis
Type 1 - mixed anaerobic and aerobic bacteria
Type 2 - mono-microbial (group A streptococci)
What profile of people are most likely to get type 1 necrotising fasciitis? (2)
Patients who have had recent abdominal surgery
Type 2 diabetics
How is necrotising fasciitis managed?
Surgical debridement followed by aggressive use of broad-spectrum antibiotics (usually benzylpenicillin and clindamycin)
With the addition of metronidazole in type 1 to cover anaerobic microorganisms
What is gas gangrene?
A specific deep-seated infection with clostridium spp. (especially clostridium perfringens) contaminating penetrating wounds
What clinical picture does gas gangrene present with?
Muscle necrosis with severe pain and swelling and crepitus on deep palpation (due to gas in subcutaneous tissue as a result of necrosis)
How is gas gangrene treated?
Surgical debridement and combination antimicrobial therapy of benzylpenicillin and clindamycin
What does the dermamatophytes refer to?
Three types of fungi commonly responsible for infections of the superficial skin layers.
How are dermatophytes transmissible?
Direct contact with infected humans/animals or by indirect contact with exfoliated hair/skin
What type of dermatophyte infection affects the body?
Tinea corporis
What type of dermatophyte infection affects the face?
Tinea faciei
What type of dermatophyte infection affects the groin?
Tinea cruris
What type of dermatophyte infection affects the feet?
Tinea pedis
What type of dermatophyte infection affects the hands?
Tinea manuum
What type of dermatophyte infection affects the nailbed?
Tinea unguium
What type of dermatophyte infection affects the scalp?
Tinea capitis
How does tinea corporis present?
Mildly itchy patches with central clearing and an advancing, scaly edge
How does tinea faciei present?
Erythematous annular lesion on the face; may or may not be itchy
How does tinea cruris present?
Intensely itchy rash in the groin with scaly edges and often extends on the inner thigh
How does tinea pedis present?
White, macerated/fissured skin around toe clefts with more scaly erythema extending onto the soles and sides of the feet
How does tinea manuum present?
Diffuse erythematous scaling of the palmar surface of the hands
How does tinea capitis present?
A spectrum of presentation from mild scaling and no hair loss to circular patches of scale and alopecia