1. Skin Infections Omar Y. Abdullah

2. Bacterial skin infections Bacterial skin infections Viral skin infections Viral skin infections Fungal skin infections Fungal skin infections

3. Bacterial skin infections

4. Why does skin get infected? There are multiple types of bacteria which are normally present on the skin. There are multiple types of bacteria which are normally present on the skin. For example: Staphylococcus epidermidis and yeasts For example: Staphylococcus epidermidis and yeasts The presence of bacteria does not automatically lead to a skin infection The presence of bacteria does not automatically lead to a skin infection What is the difference between colonisation and infections???

5. Colonisation: Bacteria are present, but causing no harm Colonisation: Bacteria are present, but causing no harm Infection: Bacteria are present and causing harm. Infection: Bacteria are present and causing harm. A break in the epidermal integrity can allow organisms to enter and become pathogenic. This can occur as a result of trauma, ulceration, fungal infection, skin disease such as eczema

6. Impetigo A highly infectious skin disease, which commonly occurs in children. A highly infectious skin disease, which commonly occurs in children.

7. The causative organism is usually Staphylococcus Aureus (>90% cases 1 ), but less often can be strep pyogenes. The causative organism is usually Staphylococcus Aureus (>90% cases 1 ), but less often can be strep pyogenes. Begins as a vesicle, which may enlarge into a bulla. Begins as a vesicle, which may enlarge into a bulla. Weeping, exudative area with characteristic honey coloured or golden, gummy crusts, which leave denuded red areas when removed. Weeping, exudative area with characteristic honey coloured or golden, gummy crusts, which leave denuded red areas when removed. May present as macules, vesicles, bullae or pustules May present as macules, vesicles, bullae or pustules Bullae are more prominent in staphylococcal infection and in infants Bullae are more prominent in staphylococcal infection and in infants

8. Impetigo Treatment:  Mild localised cases - use topical antibiotic Polyfax  Widespread or more severe infections – use systemic antibiotics, such as flucloxacillin (or erythromycin if penicillin allergic)

9. Folliculitis Inflammation of the hair follicle. Inflammation of the hair follicle. Presents as itchy or tender papules and pustules at the follicular openings. Presents as itchy or tender papules and pustules at the follicular openings. Complications include abscess formation and cavernous sinus thrombosis if upper lip, nose or eye affected. Complications include abscess formation and cavernous sinus thrombosis if upper lip, nose or eye affected.

10. Most common cause is Staph Aureus. Most common cause is Staph Aureus. Other organisms to consider include: Other organisms to consider include: Gram negative bacteria – usually in patients with acne who are on broad spec antibiotics Gram negative bacteria – usually in patients with acne who are on broad spec antibiotics Pseudomonas (“Hot tub folliculitis”) Pseudomonas (“Hot tub folliculitis”) Yeasts (candida and pityrosporum) Yeasts (candida and pityrosporum)

11. Folliculitis treatment Topical antiseptics such as Chlorhexidine Topical antiseptics such as Chlorhexidine Topical antibiotics, such as Fusidic acid or Mupirocin Topical antibiotics, such as Fusidic acid or Mupirocin More resistant cases may need oral antibioics such as Flucloxacillin More resistant cases may need oral antibioics such as Flucloxacillin Hot tub folliculitis – ciprofloxacin 2 Hot tub folliculitis – ciprofloxacin 2 Gram negative – trimethoprim Gram negative – trimethoprim

12. Cellulitis Infection of the deep subcutaneous layer of the skin Infection of the deep subcutaneous layer of the skin Presents as a hot, tender area of confluent erythema of the skin Presents as a hot, tender area of confluent erythema of the skin Can cause systemic infection with fever, headache and vomiting. Can cause systemic infection with fever, headache and vomiting. Erysipelas is more superficial and has a more well demarcated border Erysipelas is more superficial and has a more well demarcated border

13. Erysipelas

14. Cellulitis Streptococcus – Group A Strep Pyogenes. Streptococcus – Group A Strep Pyogenes. Others include Group B, C, D strep, Staphylococcus Aureus, haemophilus influenzae (children) and anaerobic bacteria (e.g Pasteurella spp. After animal bites) Others include Group B, C, D strep, Staphylococcus Aureus, haemophilus influenzae (children) and anaerobic bacteria (e.g Pasteurella spp. After animal bites)

15. Treatment of cellulitis Oral Flucloxacillin or erythromycin if allergic Oral Flucloxacillin or erythromycin if allergic Co-amoxiclav in facial cellulitis Co-amoxiclav in facial cellulitis If severe systemic upset, may require admission for IV antibiotics. If severe systemic upset, may require admission for IV antibiotics. After the acute attack has settled, especially in recurrent episodes – consider the underlying cause After the acute attack has settled, especially in recurrent episodes – consider the underlying cause

16. Orbital cellulitis – refer urgently

17. Staphylococcal Scalded Skin Syndrome A superficial blistering condition caused by exfoliative toxins of certain strains of Staph Aureus A superficial blistering condition caused by exfoliative toxins of certain strains of Staph Aureus Usually in children less than 5 yrs old Usually in children less than 5 yrs old Characterised by blistering and desquamation of the skin and Nikolsky's sign (shearing of the epidermis with gentle pressure), even in areas that are not obviously affected Characterised by blistering and desquamation of the skin and Nikolsky's sign (shearing of the epidermis with gentle pressure), even in areas that are not obviously affected

18. begins with a prodrome of pyrexia and malaise, often with signs and symptoms of an upper respiratory tract infection begins with a prodrome of pyrexia and malaise, often with signs and symptoms of an upper respiratory tract infection discrete erythematous areas then develop and rapidly enlarge and coalesce, leading to generalised erythema - often worse in the flexures with sparing of the mucous membranes discrete erythematous areas then develop and rapidly enlarge and coalesce, leading to generalised erythema - often worse in the flexures with sparing of the mucous membranes large, fragile bullae form in the erythematous areas and then rupture large, fragile bullae form in the erythematous areas and then rupture

19. Complications include hypothermia, dehydration and secondary infection. Complications include hypothermia, dehydration and secondary infection. Treatment: ABC, refer urgently for IV antibiotics and fluids, may need referral to tertiary burns centre Treatment: ABC, refer urgently for IV antibiotics and fluids, may need referral to tertiary burns centre

20. What is the diagnosis? Painful red nodule

21. Furunculosis (boils) and carbuncles Deeper Staphylococcal abscess of the hair follicle Deeper Staphylococcal abscess of the hair follicle Coalescence of boils leads to the formation of a carbuncle Coalescence of boils leads to the formation of a carbuncle Treatment is with systemic antibiotics and may need incision and drainage. Treatment is with systemic antibiotics and may need incision and drainage. Consider looking for underlying causes, such as diabetes Consider looking for underlying causes, such as diabetes

22. Erythrasma Colonisation of axillae or groin with Corynebacterium Minutissimum. Colonisation of axillae or groin with Corynebacterium Minutissimum. Presents as a fine, reddish brown rash in the flexures, which is sharply marginated. Presents as a fine, reddish brown rash in the flexures, which is sharply marginated. Often misdiagnosed as a fungal infection Often misdiagnosed as a fungal infection Woods light illumination produces a characteristic coral-pink fluorescence. Woods light illumination produces a characteristic coral-pink fluorescence. Treatment is with topical fusidin cream. Treatment is with topical fusidin cream.

24. When you use the Wood’s light, the skin lesion shows a dramatic coral pink fluorescence. When you use the Wood’s light, the skin lesion shows a dramatic coral pink fluorescence.

25. Viral Skin Infections

26. Viral warts and verrucas Caused by human papilloma virus Caused by human papilloma virus Main types, common, plane and plantar Main types, common, plane and plantar Very common Very common Disappear spontaneously eventually Disappear spontaneously eventually If treatment is needed, options include: If treatment is needed, options include: Salicylic acid topically – needs daily treatment and can take months Salicylic acid topically – needs daily treatment and can take months Cryotherapy Cryotherapy Imiquimod cream Imiquimod cream

29. Molluscum contagiosum Caused by MC virus Caused by MC virus Common in children, but can occur at any age Common in children, but can occur at any age Spread by direct contact Spread by direct contact Presents as multiple small, pearly, dome-shaped papules with central umbilication Presents as multiple small, pearly, dome-shaped papules with central umbilication Can occur at any site Can occur at any site Usually resolve spontaneously in 6-18 months Usually resolve spontaneously in 6-18 months Resolution is heralded by the development of erythema around the lesions. Resolution is heralded by the development of erythema around the lesions. Treatment is not usually necessary – simple reassurance and advice about reducing transmission. Treatment is not usually necessary – simple reassurance and advice about reducing transmission. If treatment is necessary, options include: If treatment is necessary, options include: Piercing the lesion with an orange stick tipped with iodine Piercing the lesion with an orange stick tipped with iodine Curretage Curretage imiquimod cream imiquimod cream

31. Herpes Zoster (Shingles ) Caused by reactivation of the chickenpox virus which has lain dormant in the dorsal root or cranial nerve ganglia Caused by reactivation of the chickenpox virus which has lain dormant in the dorsal root or cranial nerve ganglia Rash is preceded by a prodromal phase of up to 5 days of tingling or pain Rash is preceded by a prodromal phase of up to 5 days of tingling or pain Then develop painful grouped vesicles/pustules on a red base in a dermatomal distribution. Then develop painful grouped vesicles/pustules on a red base in a dermatomal distribution. Most common in thoracic and trigeminal areas Most common in thoracic and trigeminal areas Lesions become purulent, then crusted Lesions become purulent, then crusted Healing takes place in 3-4 weeks Healing takes place in 3-4 weeks

33. Shingles treatment Aciclovir 800mg 5 times daily, for 7 days Aciclovir 800mg 5 times daily, for 7 days Rest, analgesia usually gabapentine. Rest, analgesia usually gabapentine. Complications include:  Post herpetic neuralgia  Secondary infection  Guillain Barre Syndrome  Occular disease

34. Post-herpetic Neuralgia Pain lasting longer than 3 months after the rash. The followings are risk factors for developing post-herpetic neuralgia? A: Older age B: More severe pain during the eruption C: Severely inflamed rash D: Prodromal pain in dermatome

35. Herpes Simplex Virus A highly contagious infection spread by direct contact A highly contagious infection spread by direct contact HSV 1 : also commonly called “coldsore” HSV 1 : also commonly called “coldsore” HSV 2 usually presents on the genitalia HSV 2 usually presents on the genitalia Primary infection is usually asymptomatic. Primary infection is usually asymptomatic. Recuurent infection presents as acute, painful gingivo-stomatitis with multiple small intra/peri- oral ulcers (but any site could be affected). Associated with fever, malaise and lymphadenopathy. Recuurent infection presents as acute, painful gingivo-stomatitis with multiple small intra/peri- oral ulcers (but any site could be affected). Associated with fever, malaise and lymphadenopathy.

36. Genital herpes Herpetic Whitlow Herpes Simplex Keratitis

37. Clinically: Grouped umbilicated vesicles/pustules on erythematous base. Clinically: Grouped umbilicated vesicles/pustules on erythematous base.Treatment: Topical aciclovir can be used: 5 times daily for 5 days. Reduces duration of attack and duration of viral shedding. Topical aciclovir can be used: 5 times daily for 5 days. Reduces duration of attack and duration of viral shedding. The correct dose of aciclovir for HSV is 200mg 5 times daily for 5 days The correct dose of aciclovir for HSV is 200mg 5 times daily for 5 days

38. Thank you