Skin 9

Question 1

what is the causes of boils?

Answer 1

Tender nodules caused by Staphylococcal infection, often an infection of the hair follicle

Also called furuncles and carbuncles

Question 2

what is carbuncle?

Answer 2

A carbuncle is a cluster of furuncles connected subcutaneously, causing scarring. May be accompanied by fever

Question 3

what is furnuncles?

Answer 3

Furuncles are common on neck, face, breasts and buttocks. Appear as nodules or pustules. Can be very painful esp. if on nose, ears etc

Question 4

what is the predisposing factors of boils?

Answer 4

Predisposing factors include:

• bacterial colonisation of skin
• hot and humid climates
  occlusion or abnormal follicular anatomy
  e.g. comedones in acneCan affect healthy young people but more common in obese, immunocompromised, elderly and/or diabetic patients

Question 5

what is the diagnosis of boils?

Answer 5

Diagnosis is by examination. Material for culture can be obtained from patients with single furuncles on nose/central face, from patients with multiple furuncles, and immunocompromised patients

Question 6

what is the symptoms of boils?

Answer 6

hard, tender, red lump surrounding a hair follicle
enlargement of the lump
pain
pus discharging from the lump
redness of the skin around the lump
may have a mild fever or feel tired and run down

Question 7

what is the treatment of boils?

Answer 7

Single lesion - intermittent hot compresses * to allow it to drain spontaneously.

Furuncle in the nose or central facial area or with multiple furuncles or carbuncles – topical antibiotics*
penicillinase-resistant beta-lactam (S.aureus resistance) - don’t want to cause MRSA resistance therefore try to avoid it.
Paracetamol / ibuprofen if painful *

Systemic antibiotics needed for larger lesions, lesions that do not respond to topical care, evidence of expanding cellulitis, immuno-compromised patients, or patients at risk for endocarditis.
Flucloxacillin (clarithromycin if allergic to penicillins) 500 mg 4x a day, 7 days *

Incision and drainage occasionally necessary

Furuncles frequently recur. Can be prevented by application of liquid soap containing either chlorhexidine gluconate with isopropyl alcohol or 2-3% chloroxylenol, or by maintenance antibiotics over 1 to 2 mo.

Question 8

what is the cause of impetigo?

Answer 8

Superficial skin infection with crusting caused by Streptococci, Staphylococci, or both. Ecthyma is an ulcerative form of impetigo.

No predisposing lesion identified in most patients but can follow any break in skin

Question 9

what is the risk factors of impetigo?

Answer 9

Risk factors include: moist environment, poor hygiene, chronic nasal carriage of staphylococci

Question 10

how are impetigo and ecthyma characteristised?

Answer 10

Presents as clusters of vesicles or pustules that rupture and develop “honey-coloured crust”.

Ecthyma characterised by small, purulent, shallow, punched-out ulcers with thick, brown-black crusts and surrounding erythema

Impetigo and ecthyma cause mild pain or discomfort. Pruritus is common, *scratching can spread infection

Highly contagious

Question 11

what are the different types of impetigo?

Answer 11

bullous
non-bullous
ecthyma

Question 12

what is bullous impetigo?
and its cause
who is it most common in?
symptoms/characteristic?

Answer 12

Caused by S. aureus
Blisters which fill with fluid then turn opaque
Blisters then burst and form a “yellow crust”
Up to 2 cm diameter
Can be confused with allergic contact dermatitis

Most common in babies
nappy area or neck folds
Other areas most common on trunk, leg, arms

Question 13

what is non-bullous impetigo?
cause
symptoms/characteristic

Answer 13

More common, around 70% of impetigo cases
Caused by S. aureus or Strep. Pyogenese

Usually starts with reddish spots that develop into small red blisters (clusters of blisters) around the mouth and nose.
1 to 2 centimeters in diameter
The clusters of blisters may spread to other skin areas.

After a few days, the blisters burst and develop a brownish-yellow crust. The surrounding skin can look red and raw.

Nonbullous impetigo is itchy, but not painful.

Question 14

what is ecthyma?
cause
characteristic
who is it more common in

Answer 14

Caused by Strep pyogenes, S. aureus or both

Pus-filled sores with a thicker crust.
Ecthyma deeper into the skin than the other forms of impetigo, and it can be more severe.

Ecthyma blisters often painful and can develop into larger, deeper sores, between 0.5 and 3 centimeters in diameter.
progress to have a thick crust surrounded by reddish-purple skin.

Most common on buttocks, thighs, legs, ankles, and feet.
untreated nonbullous or bullous impetigo can develop into ecthyma.

The ecthyma lesions heal slowly and may leave scars.

CAUSE A SCAR unlike the other impetigo.

Question 15

what is the treatment of impetigo and ecthyma?

Answer 15

Localised disease treated with fusidic acid
(2%, 3-4 times daily).

If MRSA, can use topical mupirocin,
( 2%, t.d.s. 10 days)

If extensive, refer for oral antibiotics
Flucloxacillin
Clarithromycin

Prompt recovery usually follows timely
treatment

Question 16

how can you diagnose impetigo and ecthyma?

Answer 16

Diagnosis is by characteristic appearance. Cultures of lesions indicated only when patient fails to respond to initial therapy. Patients with recurrent impetigo require nasal culture.

Question 17

what is photosensitivity?
symptoms
causes/risk factor
treatment

Answer 17

Poorly understood reaction of skin to sunlight. Probably involves immune system

Can get redness, rash, urticaria. Within minutes of exposure to sunlight. In extreme cases can lead to dizziness, wheezing and other systemic problems.

Can occur after exposure to certain drugs or chemicals (e.g. phenothiazines).

Treatment varies depending on cause. If unusual reactions occur after brief sun exposure, suspect systemic disease or underlying skin disorder e.g. lupus erythematosus. If sunlight induces skin reaction following use of chemicals e.g. in cosmetics, use topical corticosteroids and avoid causative agent

Question 18

what is drug-induced photosensitivity?
Photoxicity
Photoallergy

Answer 18

Drug-induced photosensitivity sub-divided into phototoxicity or photoallergy

Photoxicity - light-absorbing compounds directly generate free radicals and inflammatory mediators. Get tissue damage, pain and erythema (like sunburn). Reaction does not require prior sun exposure, can appear in any person, and is highly variable. Typical causes of phototoxic reactions include: topical (e.g. perfumes, coal tar) or ingested (e.g. tetracyclines, psoralen-containing plants) agents. Only on sun-exposed skin.
(caused due to tissue damage)

Photoallergy - type IV (cell-mediated) immune response; light absorption causes structural changes in drug/chemical, allowing it to bind to tissue protein and function as a hapten. Prior exposure is required. Typical causes of photoallergic reactions include: aftershave lotions, sunscreens, and sulfonamides. Reaction may extend to non-sun-exposed skin. Symptoms include: erythema, pruritus, and sometimes vesicles.
(immunological)

Question 19

what is an example of a drug which induces photo toxicity?

Answer 19

Sulfasalazine induced photo toxicity

Question 20

what is burns?

Answer 20

Burns are injuries of skin or other tissue caused by thermal, radiation, chemical or electrical contact.

Greater the % of body surface area (BSA) involved, greater the risk of developing systemic complications.

Question 21

what are the different types of burns?

Answer 21

Thermal burns - from any external heat source (flame, liquids, solid objects, gases)

Radiation burns - commonly result from prolonged exposure to solar UV radiation (sunburn). Can be from other sources (e.g. tanning beds, X-rays, non-solar radiation)

Chemical burns - strong acids or alkalis (e.g. cement), phenols, cresols. Skin/deeper tissue necrosis due to agents may progress over hrs

Electrical burns - result from electrical generation of heat. Skin/deeper tissue damage may result despite minimal apparent cutaneous injury.

Question 22

how are burns classified?

Answer 22

Classified by depth (1st degree, partial thickness, full thickness) and % total body surface area involved
1st degree
2nd degree
3rd degree

Question 23

what does burns cause?

Answer 23

Burns cause protein denaturation and coagulation necrosis. Platelets aggregate, vessels constrict around coagulated burned tissue. Get inflammation around damaged zone and can get bacterial infection through damaged epidermal layer. Leads to oedema and external fluid leakage. Heat loss can be significant because thermoregulation of damaged dermis is impaired and fluid leakage increases evaporative heat loss.

Question 24

what is first degree burn?

Answer 24

First degree - most common type of burn. Burns are red, blanch markedly with light pressure, are painful and tender. Limited to epidermis

Question 25

what is second degree burn?

Answer 25

Second degree (partial thickness) - involve part of dermis. Sub-divided into superficial and deep.

Superficial 2nd degree burns involve upper half of dermis; heal within 2-3 wks. Rarely scar in this period unless become infected. Skin is red/white, blanch with pressure. Intense pain and tender. Vesicles develop within 24 hr.

Deep 2nd degree burns involve bottom half of dermis, take >3 wk to heal and scarring is common. May be white, red or mottled. Do not blanch and less painful/tender than more superficial burns. Vesicles may develop. Burns tend to be very dry.

Question 26

what is third degree burn?

Answer 26

Third degree (full thickness) - extend through entire dermis and into underlying fat.

Question 27

what is the treatment of burn?

Answer 27

Burns are examined/treated as soon as patient is stable

Estimate extent of burn (can use size of patient’s hand print as rough indication as is ~1% Body Surface Area)

First priorities are same as for any injured patient (airway, breathing, circulation). Remove clothing that covers burn. Flush chemicals (except powders that are brushed off first) with water. Burns caused by acids, alkalis etc should be flushed with copious amounts of water for at least 20 mins. Small burns can be immersed early in cold water until pain subsides (although this will not limit depth of injury)

IV fluids given to patients who are in shock or with burns >15% BSA

Hypothermia/pain treated appropriately

After cleaning wound, cover burn with topical antibacterial salve (e.g. 1% silver sulphadiazine) and sterile dressing. Prophylactic antibiotics not given

Depending on severity, patient might need to be hospitalised.

Dressings are changed daily. Burn cleaned completely with water. Apply new layer of antibacterial salve and re-apply clean dressing

Surgery (grafting) is indicated for all third degree burns and for burns that do not heal within 3 wks (most deep 2nd degree burns).

Question 28

how does grafting (surgery work?)

Answer 28

Graft of a layer of healthy skin eg. 5cm2 from thigh.
Cut into a mesh - covers 10-20cm2.