Infections and Infestations

Question 1

Describe change on skin of newborn baby in first few days of life?

Answer 1

Baby goes from sterile womb environment to non-sterile world.

Skin is colonised by 1000s of bacteria

Baby commonly gets rash called Pitorosporum

Question 2

What are some common bacteria and funghi that normally live on our skin?

Answer 2

Staph Aureus

Staph Epidermis

Candida

Question 3

Common signs of infection?

Answer 3

Remember classic signs

Rubor (Redness)

Dolor (Pain)

Calor (Heat)

Tumour (Swelling)

Pus

Blisters etc

Question 4

How do you diagnose infection?

Answer 4

History

Exam

Investigations

Question 5

What are some common investigations?

Answer 5

Swabs

Bloods (LFTs, U&Es etc)

Biopsy

Question 6

What are the common infective agents of the skin?

Answer 6

Staph Aureus

Strep Pyogenes

Question 7

What are the 4 bacterial infections to note?

Answer 7

Impetigo

Cellulitis

Oedema Blisters

Lipodermatosclerosis

Question 8

What is Impetigo?

Answer 8

Most common bacterial infection in children

Honey crusted scabs (may also have Bulla) which are made worse by scratching

Caused by Staph Aureus and Strep Pyogenes

Question 9

How do you treat Impitigo?

Answer 9

Topically -

Fusidic Acid 3/4 times a day for 5 days

Mupirocin 3/4 times a day for 5 days (if MRSA)

Orally (if systemic, severe or bullous) -

Flucloxacillin - 4x times daily for 7 days

Erythromycin - 4x times daily for 7 days

Question 10

What is Cellulitis?

Answer 10

Bacterial infection caused by Staph Aureus and Strep Pyogenes

Causes red swollen lower limbs, may be hot

Question 11

Where is cellulitis common?

Answer 11

Lower limb - below the knee

Question 12

What are the symptoms of cellulitis?

Answer 12

Tender and hot

If the infection is extensive then fever as well

Question 13

How do you diagnose Cellulitis?

Answer 13

Take swab and send to lab

Start on empirical Abx

IV Flucloxacillin every 6 hours

AND Benzylpenicillin every 6 hours

Review Abx after 48 hours and check bacterial swab results

Question 14

If the Cellulitis isnt better in a week what might have happened?

Answer 14

Diagnosis wrong - think of differential diagnosis eg

Necrotising Fasciitis

Venous Eczema

DVT

Allergic Dermatitis

Question 15

What is Ersypelas?

Answer 15

Acute, sometimes recurrent disease caused by a bacterial infection, characterized by large raised red patches on the skin.

More superficial than cellulitis

Caused by strep

Skin is raised and inflamed over infected area

Question 16

What are Oedema Blisters?

Answer 16

Exacerbation of Oedema

Can be misdiagnosed as Cellulitis as affects lower limbs and dorsum of feet

Causes redness and swelling

Question 17

What causes Lipodermatosclerosis?

Answer 17

Poor circulation in lower limbs causes inflammation of fat

Often hints at underlying venous issues

Question 18

How do you treat Lipodermatosclerosis?

Answer 18

Compression stocking

Treat underlying venous disease or refer to specialist

Topical Steroids for inflamm

Question 19

Name 2 common forms of Fungal infection

Answer 19

Tinea (Moulds) - Dermatophyte

Candidiasis (Yeasts) - red circles

Question 20

Name some Tinea infections based on body area affected?

Answer 20

Tinea Corporis - Body (Ringworm)

Tinea Capitis - Head/Scalp

Tinea Cruris - Groin

Tinea Pedis - Foot

Question 21

How do you diagnose fungal infections?

Answer 21

Skin scraping, hair or nail sample

Incubate in lab - results can take weeks

Question 22

How do you treat tinea of scalp and nails?

Answer 22

Oral antifungals

Question 23

How do you treat Tinea of the body, hands, feet etc? (NOT scalp and nails)

Answer 23

Topical antifungals eg

Clotrimazole

Terbinafine

Question 24

What are the best agents to treat tinea pedis (dermatophyte fungi)?

Answer 24

Clotrimazole or terbinafine

Question 25

What happens when you use topical steroids on tinea?

Answer 25

Loss of scaly appearance | (tinea incognita)

Question 26

Who else besides the patient do you need to treat if Tinea infection is present?

Answer 26

Family and close contacts

Question 27

What common condition is Tinea sometimes mistaken for?

Answer 27

Eczema

Question 28

What is the most common yeast infection?

Answer 28

Candida albicans- grows on moist areas (obese people who are unable to wash well)

Question 29

What is Candida Albicans?

Answer 29

Common yeast infection - likes warm, moist environments

Question 30

What does candida albicans look like?

Answer 30

Brick red erythema Satellite pustules (commonly foound underneath the breasts or inbetween the fingers of people who have a lot of wetness on their hands - occupation related)

Question 31

How do you treat Candida Albicans?

Answer 31

Topical antifungal eg Miconazole Ketoconazole ZOLES

Question 32

What is Intertrigo and how is it linked to fungal infections?

Answer 32

Intertrigo is inflamm of skin folds eg areas where skin may rub more (under breasts etc) This inflamm can be made worse by bacterial or fungal infections eg Candida Albicans commonly (warm and moist)

Question 33

What are some common viral infections you may see?

Answer 33

Viral Warts DNA Pox Virus Herpes Simplex Virus Herpes Zoster Virus

Question 34

Describe Viral Warts

Answer 34

Common in children, often on hands Resolve usually on their own within few years Shouldnt limit child - plaster over them If persist can freeze off

Question 35

Describe DNA Pox Virus

Answer 35

Papules with a central dent Treat with 5% Potassium Hydroxide to papule - body will launch immune response and then recognise from then on

Question 36

Describe Herpes Simplex Virus

Answer 36

Type 1 = Coldsores Type 2 = Genital Warts Treat with Aciclovir

Question 37

What is the pathogenesis of the herpes simplex virus?

Answer 37

Primary infection Latent period Reactivation

Question 38

Who is likely to suffer from worse cinical episodes from the herpes simplex virus?

Answer 38

The immunosuppressed Those with atopic eczema

Question 39

Describe the Herpes Zoster Virus

Answer 39

Chickenpox in children - usually build immunity to it Can reactivate in adults as SHINGLES Very harmful to others who havent had pox before so IPC measures very important

Question 40

What is the pathogenesis of the herpes zoster virus?

Answer 40

Primary exposure Chicken pox Latent infection Reactivation Shingles (pain / constitutional symptoms) about 4 days after - rash The rash usually tracks around the body - however it does not cross the midline of the body

Question 41

Name a common INFESTATION

Answer 41

Scabies

Question 42

What is the main symptoms in scabies?

Answer 42

Itching - may also see red raised bumps which hints at burrows

Question 43

What causes the itching in scabies?

Answer 43

A protein in mite droppings

Question 44

Where does scabies normally infect?

Answer 44

Hands & Feet Also areas of body hair eg genitals, breasts, belly button etc

Question 45

How is scabies spread?

Answer 45

Long skin-skin contact (about a minute), also bed sheets, clothing etc

Question 46

What causes the rash associated with scabies, describe the rash

Answer 46

Allergic rash is usually on the sides of the torso – lesions here do not have mites – they are the allergic manifestation of the mites

Question 47

How do we diagnose Scabies?

Answer 47

A) Skin scraping/swab and send to lab B) Also useful to draw circle in ink around suspected burrow and wipe away ink - if some doesnt budge its because ink has entered the burrow

Question 48

How do we treat scabies?

Answer 48

PERMETHRIN CREAM - applied head to toe for 8 hours Do again 7 days later Also treat family/close contacts - wash bedding etc Treat ongoing itch symptomatically with steroids for anti-inflammatory effects.