6. Infections and Infestations Flashcards
= Most commonly caused by Staph aureus
= Tinea is caused by a fungus that attacks hair, nails and skin
Which of the following statements is true?
Common warts are caused by the human papilloma virus.
Which of the following statements is true?
Scabies is caused by an insect that burrows into the skin
Which of the following statements is true?
= The majority of Staph Aureus infections can be effectively treated with oral cephalosporin.
What is Impetigo?
- 3 Presentations of Impetigo?
- If caused by S.pyogenes, what is a possible complication of impetigo?
= post-streptococcal glomerulonephritis
Aetiology of Impetigo?
Transmission of Impetigo?
Diagnosis of Impetigo?
Treatment of Impetigo? (10 points)
- What must you also consider in terms of managing the spread of impetigo?
What is Cellulitis? What is Erysipelas?
- Predisposing conditions?
Cellulitis & Erysipelas?
- Site & Aetiology?
- Differential Diagnoses?
Cellulitis & Erysipelas?
- Diagnosis?
- Treatment? (6)
What is Community-Acquired MRSA?
- 6 Populations at high risk?
Community-Acquired MRSA
- Risk factors?
- Investigations?
- Management?
What is Folliculitis?
- Aetiology?
Folliculitis
- Presentation?
- Management?
Boils
- What are they?
- Who gets them?
- Aetiology?
- Management - Steps 1-3?
Management
1. The primary treatment of small fluctuant lesions is incision and drainage under local anaesthesia. Larger abscess cavities require lodoform gauze packing with replacement of the dressing when saturated.
2. When antibiotic treatment is indicated, the choice of antibiotic should be guided by culture and sensitivity results, given the increasing incidence of methicillin resistance.
3. Recurrent boils are often due to staph carrier state. Recurrent infection and eradication of carrier status may be challenging and are indications for referral to a dermatologist or infectious disease specialist.
What is Paronychia?
- 2 Types?
What kind of genital infections do children get?
What is Otitis Externa?
- Acute vs. Chronic?
- 3 Predisposing factors?
Acute = usually infective. The most common pathogen is S.aureus.
Chronic = usually a dermatosis such as psoriasis or seborrhoeic dermatitis, with or without a secondary infection. Many pathogens may be encountered, including S.aureus, Pseudomonas aeruginosa, C.albicans, and other fungal infections.
Otitis Externa
- Management? (4)
- A swab of discharge is helpful.
- Debris in the ear canal should be cleaned out and antibiotic ear drops used particularly for acute otitis externa.
- Corticosteroid ear drops may help to settle inflammation.
- Environmental modifications should be implemented.
What is Herpes Simplex Virus?
- Transmission?
- 2 Types?
Type 1 - usually causes oral infections (herpes stomatitis and herpes labialis ‘cold sores’)
Type 2 - Causes Genital infections.
- Some crossover does occur and HSV-1 is becoming a common cause of genital herpes.
- Oral HSV-1 infection recurs more frequently than HSV-2.
- Genital HSV-2 recurs more often than genital HSV-1.
- While most HSV infections occur in mucous membranes, infections can occur on the fingers (herpetic whitlows) or elsewhere on the skin.
Herpes Simplex Virus
- Presentation?
Herpes Simplex Virus
- Diagnosis?
- 2 Types?
What is Varicella?
- Presentation?
Varicella
- 8 Complications?
- 7 Differential diagnoses?
Varicella
- Diagnosis?
- Treatment?
Diagnosis of Varicella
- The diagnosis of varicella is made clinically and can be confirmed by viral swab PCR from base of vesicle.
What is Herpes Zoster?
- Presentation?
- Which Sign?
Herpes Zoster
- Diagnosis?
- Treatment?
Diagnosis of Herpes Zoster
- The diagnosis of herpes zoster is made clinically and can be confirmed by viral swab PCR from base of vesicle.
What is Molluscum Contagiosum?
- Presentation?
Molluscum Contagiosum
- Transmission - 2 Groups?
- 2 Differentials?
Molluscum Contagiosum
- Management? (2)
- Controlling Spread? (6)
Management of Molluscum Contagiosum
1. As Molluscum Contagiosum usually resolves spontaneously (average 8 months), and only occasionally leave a small pitted scar, an option is to allow the virus to run its course.
2. If treatment is preferred, options include:
- Cryotherapy
- Curettage
- Tape occlusion
Warts
- What are they?
- Transmission? (4)
Warts
- Presentation?
- Differential diagnoses?
- Management? (4)
Management
1. Spontaneous resolution usually occurs within 2 years and treatment is not required.
2. If treatment is desired, options include topical salicylic acid and cryotherapy.
3. Specialist referral is recommended if conservative treatment has failed, and the warts are causing distress or embarassment.
4. HPV vaccine is part of the national immunisation program, and prevents multiple types of HPV that cause genital warts and cervical cancer.
What are Viral Exanthems?
- 2 main presentations in children?
Measles
- Presentation?
- Diagnosis?
- 3 Complications?
- Management? (3)
- Diagnosis is clinical and confirmed on serology.
- Complications include;
1. pneumonia
2. otitis media
3. encephalitis
Rubella
- Presentation?
- Diagnosis?
- Complications?
- Management? (3)
- Diagnosis is clinical and confirmed on serology.
- Complications include;
1. Infection in the first trimester of pregnancy has a 50% risk of congenital rubella syndrome (sensorieneural deafness, CNS dysfunction, cataracts, cardiac defects).
What is Hand, Foot, and Mouth Disease?
- Presentation?
- Transmission?
Transmission - This occurs via secretions from the skin and mouth, or with faeces.
6 Differentials for Hand, Foot, and Mouth Disease?
Hand, Foot, and Mouth Disease
- Diagnosis?
- Management? (3)
Parvovirus
- Presentation? (4)
- Differential Diagnoses?
Parvovirus
- Management?
3 Common fungal diseases?
Tinea
- What is it?
- Clinical features?
- 9 Classifications?
What type of tinea is this?
= Tinea Corporis (body and limbs)
What type of tinea is this?
What type of tinea is this?
3 Well-recognised presentations of tinea pedis?
What is Tinea Manuum?
What type of tinea is this?
= Tinea Capitis (Scalp)
- This is a fungal infection of the scalp.
- It is virtually only seen in pre-pubertal children and is usually due to zoophilic fungi acquired from pets.
What type of tinea is this?
What is Tinea Barbae?
- 2 clinical patterns?
What is seen here?
- Predisposing factors?
The toenails are affected in 80% of cases. Predisposing factors include;
1. trauma
2. poor fitting footwear
3. immunosuppression
4. ageing
5. other underlying disease such as psoriasis
Onychomycosis presents with discoloured crumbly nails.
What type of tinea is this?
Differential diagnoses for:
- Tinea in general? (5)
- Tinea capitis? (2)
- Tinea faciei? (4)
- Onychomycosis? (4)
Diagnosis of Tinea?
Management of Tinea?
Topical Treatment - with terbinafine is indicated for localised tinea.
Oral Treatment - is indicated if tinea is extensive or if hair-bearing areas are involved. Griseofulvin or terbinafine may be used. Griseofulvin is slower to work, requiring more weeks of treatment.
Pityriasis versicolor
- What is it?
- 3 Predisposing factors?
- Presentation?
Predisposing factors:
1. hot conditions
2. tropical climates
3. occupations involving physical exertion and heavy sweating
Pityriasis versicolor
- Diagnosis?
- Management?
What is the most common fungus to cause follicular eruptions/folliculitis?
= Malassezia
Fungal Folliculitis
- Clinical features?
- Diagnosis?
- Management?
Cutaneous Candidiasis
- What is it?
- 11 Predisposing factors?
Predisposing Factors – Cutaneous Candidiasis
1. Maceration of skin
2. Warm, moist, and occlusive conditions
3. Immobility
4. Diabetes
5. Obesity
6. Topical and systemic immunosuppressive therapy
7. Broad-spectrum systemic antibiotics
8. Pregnancy
9. OCP use
10. Infancy
11. Decreased host cell-mediated immunity
Cutaneous Candidiasis
- Diagnosis?
- Differentials?
- Management?
Diagnosis - C albicans is easily grown in culture and a swab usually confirms the diagnosis.
Differentials
1. Flexural psoriasis
2. Irritant contact dermatitis particularly in intertriginous sites
3. Bacterial infection
4. Herpes simplex infection
Oral Candidiasis
- What is it?
- Presentation?
- Diagnosis?
- Treatment?
Diagnosis - MC&S
Treatment
1. Manage underlying abnormalities
2. Topical therapy includes miconazole, nystatin, or amphotericin
3. In immunocompromised patients, systemic treatment with fluconazole or itraconazole may be required.
Vaginal Candidiasis
- 2 Ways it may present?
Outline how a fungal specimen collection is performed and the equipment required.
- 3 Types of specimen collection?
Scabies
- What is it?
- Transmission?
- Clinical features?
Scabies is caused by infestation with a tiny eight-legged arachnid.
Scabies
- Diagnosis?
- Management?
- Controlling the Spread? (3)
**Scabies – Controlling the Spread **
1. Infected patients should be excluded from school and work.
2. All close and household contact should be treated at the same time, regardless of symptoms.
3. Clothes and linen should undergo hot wash (>50degrees) and carpets and furniture vacuumed.
Head Lice
- What are they?
- Transmission?
- Clinical features?
Transmission - The infestation is spread by head to head contact.
Head Lice
- Diagnosis?
- Management?
- Controlling the Spread?
Controlling the Spread
1. It is important to wash pillow cases on hot cycles, and combs and brushes in hot water (>60degrees).
2. Family and close physical contacts should be examined and treated if lice are found.
3. The patient’s school should be notified, but it is not necessary to exclude children from school after their intial treatment.
Bites
- Most common causes?
- Clinical features?
- Management?
The most common causes of bites are insects (mosquitoes and fleas) and in some areas arachnids (grass ticks).
