2. Prof.Dr.Nabil Kamel

4. Defense Against bacteria
1‐Dry surface.
2‐ Intact surface.
3‐ Desquamating surface.
4‐ Sebum with its unsaturated fatty acids.
5‐ Normal Flora.

6. Impetigo
Definition:
Impetigo is a contagious superficial pyogenic infection
of the skin.
Two main clinical forms are recognized:
bullous impetigo
Non bullous impetigo or (impetigo contagiosa of Tilbury
fox)

7. may be caused
by
stapylococcus
aureus, by
streptococci or
by both
organisms
together.
non
bullous
impetigo
staphylococcal
disease
bullous
impetigo

8. In bullous impetigo
The epidermis splits just
below the stratum
corneum or granulosum
forming large blisters.
Neutrophils migrate
through the spongiotic
epidermis into the blister
cavity which may also
contain cocci.
The upper dermis contains
an inflammatory infiltrate
of neutrophils and
lymphocytes.
Non bullous impetigo
Similar to bullous
Except that blister
formation is slight and
transient.

9. Impetigo
The face especially around the nose
and mouth and the limbs are the sites
most commonly affected, but
involvement of the scalp and the body
especially in children with atopic
dermatitis or scabies.

10. Impetigo
Clinical features:
In bullous impetigo, the bullae are less
rapidly ruptured and become much larger.
the contents are at first clear later cloudy.
after rupture thin flat brownish crusts are
formed, central healing and peripheral
extension may give rise to circinate lesions.
the lesions may occur anywhere.
regional adenitis is rare.

11. Impetigo
In non‐bullous impetigo, the initial lesion is very
thin‐walled vesicle on an erythematous base, the
vesicle ruptures so rapidly that it is seldom seen as
such.
The exuding serum dries to form yellowish brown
crusts. The crusts eventually dry and separate to
leave erythema which fades without scarring.
In severe cases there may be regional adenitis with
fever and other constitutional symptoms.

12. Impetigo
Complications:
Cellulitis.
post streptococcal acute glomerulonephritis.
the latent period for development of nephritis
after streptococcal infection is 18‐21 days, raising
the possibility that early treatment of skin
infection might offer a better chance of
preventing the renal disease.
scarlet fever .
urticaria and erythema mulitiforme may follow
streptococcal impetigo.

13. Impetigo
Removal of infected crusts with washing with soap
and water or potassium permanganate compresses
1/8000 concentration help also in the treatment.
proper hygienic measure and eradication of
predisposing factors such as insect bites,
pediculosis, scabies and minor tauma reduce the
transmission of infection.

23. Clinical Types of Impetigo
Bullous.
Circinate.
Nonbullous, crusted, Telbery Fox.
Secondary.
Ecthyma.
Follicular, ostial, Bock hart.

24. Impetigo
Treatment:
In mild and localized infection a local antibiotic as
mupirocin oint may be enough.
In both Staph and Strept infection. fusidic acid is also
effective against both organisms but in order to reduce the
likelihood of the development of resistance because of its
value in systemic infection it may be better to restrict its
use.
Topical neomycin and bacitracin are often used in
combination.
If the infection is widespread or severe or is accompanied
by lymphadenopathy or suspect a nephritogenic
streptococcus an oral antibiotic such as flucloxacillin or
erythromycin is indicated.

25. Impetigo
Removal of infected crusts with washing with soap
and water or potassium permanganate compresses
1/8000 concentration help also in the treatment.
proper hygienic measure and eradication of
predisposing factors such as insect bites,
pediculosis, scabies and minor tauma reduce the
transmission of infection.

26. ECTHYMA

27. Ecthyma
Definition:
is a pyogenic infection of the skin
characterized by the formation of
adherent crusts ,beneath which
ulceration occurs.

28. Ecthyma
It was formerly regarded as a
streptococcal.however other cases caused by
strept and staph and others caused by staph.
the disease may affect children and adults.
poor hygiene and malnutrition are
predisposing factors and minor injuries or
scabies may determine the site of the
lesions.

29. Ecthyma
Clinical features:
Small bullae or pustules on an erythematous base are
soon covered by hard crusts of dried exudates.
the base may become indurated and a red
oedematous areola is often present.The crust is
removed with difficulty to reveal a purulent irregular
ulcer.
Healing occurs after a few weeks with scarring.
Autoinoculation may lead to multiple lesions.
the buttock ,thighs and legs are most commonly
affected.

33. Ecthyma
Treatment:
Improved hygiene and nutrition and
treatment of scabies and any other
underlying disease are important.
the antibiotic chosen should be active
against both strept and staph.

34. CELLULITIS AND
ERYSIPELAS

35. Cellulitis and erysipelas
Definition:
Cellulitis is strictly an acute, subacute or chronic
inflammation of loose connective tissue of the
subcutaneous tissue in which an infective generally
bacterial cause is responsible.
Erysipelas is a bacterial infection of the dermis and
upper subcutaneous tissue,
its main feature is a well‐defined raised edge reflecting
the more superficial (dermal) involvement.
however cellulitis may extend superficially and deeply so
that in many cases the two processes coexist and it is
impossible to make a distinction.

36. Cellulitis and erysipelas
Bacterially:
Cellulitis and erysipelas are predominantly
streptococcal diseases.
in cellulitis, staph is occasionally implicated
alone or together with strept.
hamophilus influenza is an important cause
of facial cellulitis in young children.

37. Cellulitis and erysipelas
Clinical features:
Erythema,heat ,swelling and pain or tenderness are
constant features.
In erysipelas the edge of the lesion is well demarcated and
raised but in cellulitis it is diffuse.
in erysipelas blistering is common and there may be
superficial hemorrhage into he blisters or in intact skin
especially in elderly people.
severe cellulitis may show bullae and can progress to
dermal necrosis.lymphangitis and Lymphadenopathy are
frequent.except in mild cases there is constitutional upset
with fever and malaise.

38. Classical erysipelas starts suddenly and systemic
symptoms may be acute and severe .
the leg is the commonest site and here there is
usually a wound even if superficial ,an ulcer or an
inflammatory lesion including interdigital fungal
are possible portal of entry.
the next most frequent site for classical
streptococcal erysipelas is the face where a
traumatic entry site is less commonly seen.
Cellulitis and erysipelas

39. Without effective treatment,complications
are common: fasciitis
,myositis,subcutaneous
abscesses,septiceamias and in some
streptococcal cases nephritis and the more
severe infection may be fatal in infants and
in the debilitated or immunosuppressed.
periorbital and orbital cellulitis may be
complicated by cavernous sinus thrombosis.
Cellulitis and erysipelas

42. CellulitisErysipelas
Strep or haemophelous
influenza
StreptOrganism
May be present or not Always present General
manifestations
Ill defined border erythema,
edema, hotness, pain,
tenderness.
Surface may show necrosis.
Well defined raised
border erythema, edema
with hotness, redness,
pain and tenderness.
Surface may show bullae
Local
Manifestations
Common on extremities Common on the faceSite
Both types may end with lymphoedema and vicous
circle i.e. edoema ppt. for cellulites

43. Cellulitis and erysipelas
Treatment:
Penicillin is the treatment of choice and should be
continued for 10 days.
in recurrent cases long acting penicillin can
prevent attacks.
in patients allergic to penicillin another drug
commonly erythromycin should be taken.
some patients may require life long prophylaxis.

44. INFLAMMATORY DISEASES
OF HAIR FOLLICLES

45. Inflammatory diseases of hair
follicles
Staphylococcal infection is a common cause of
superficial folliculitis.
follicular impetigo of Bockhart is an infection of the
follicular osteum with staph aureus. it is commonest in
childhood and occur mainly in the scalp or scalp
margins or on the limbs.
the individual lesion is a yellow pustule sometimes
with a narrow red areola. the pustules develop in
groups and may heal within 7‐10 days, but sometimes
become chronic.

48. Inflammatory diseases of hair
follicles
Treatment:
Mild staphylococcal folliculitis is often self
limiting.
in more severe cases antibiotics topical or
systemic may be required.
if the infection is persistent or recuurent,the
usual sites of staphylococcal carriage (nose
and perineum)should be thought of in the
patient and his or her contacts.

49. FURUNCLE(BOIL)

50. Furuncle(Boil)
Definition:
A furuncle is an acute, usually necrotic
infection of a hair follicle with staph
aureus.

51. Furuncle(Boil)
Etiology:
Common in adolescence and early adult life the
infection strain of staphylococcus is usually also
present in the nares or the perineum.
from the sites of carriage the infection is disseminated
by the fingers and by clothing. mechanical damage to
the skin even the friction of collars and belts may
determine the distribution of the lesions.
malnutrition is an important predisposing factor in
some countries. however in a high proportion of cases
no convincing predisposing factor can be responsible.

52. Pathology:
A furuncle is an abscess of a hair
follicle, usually of vellus type, the
perifollicular abscess is followed by
necrosis with destruction of the
follicle.
Furuncle(Boil)

53. Clinical features:
A furuncle first presents as a small follicular
inflammatory nodule soon becoming
pustular and then necrotic and healing after
discharge of a necrotic core to leave a
violaceous macule and a scar.
on the upper lip and cheek cavernous sinus
thrombosis is a rare and dangerous
complication.
Furuncle(Boil)

54. The sites commonly involved are the face
and neck,the arms,the fingers,the buttocks
and anogenital region.
attacks may consist of a single crop or
multiple crops at irregular intervals which
continue for many months or even years.
Furuncle(Boil)

58. Treatment:
Flucloxacillin systemically or another
penicillinase resistant antibiotic.
a topical antibacterial agent reduces
contamination of the surrounding skin.
occlusive dressings should be avoided.
in recurrent cases exclude diabetes. nasal
and perineal carriage should be sought in
the patient and other household members.
Furuncle(Boil)

59. CARBUNCLE

60. Carbuncle
Etiology:
A carbuncle is a deep infection of a group of
contiguous follicles with staph.aureus
accompanied by intense inflammatory
changes in the surrounding and underlying
connective tissues.
they may be seen in the apparently healthy
but are more common in the presence of
diabetes ,malnutrition, cardiac failure and
during prolonged steroid therapy.

61. Clinical features:
Painful, hard red swelling. it increases in size
for a few days to reach a diameter of 3‐10 cm or
more. suppuration beginning after 5‐7 days
and pus is discharged from the multiple
follicular orifices. necrosis of the intervening
skin usually occurs.
Carbuncle

62. Most lesions are on the back of the neck,the
shoulders or the hips and thighs.
constitutional symptoms may accompany or
precede the development of the carbuncle in the
form of: Fever , malaise and prostration which may
be severe if the carbuncle is large or the patient’s
general condition is poor.
in favourable cases healing slowly takes place to
leave a scar.
in bad general condition, death may occur from
toxaemia.
Carbuncle

64. Treatment:
Flucloxacillin or another penicillinase
resistant antibiotic should be given.
Diabetes or other possible underlying
conditions should be thought of.
Carbuncle

65. SYCOSIS

66. Sycosis
Definition:
Sycosis is a subacute or chronic
pyogenic infection involving the whole
depth of the follicle.

67. Etiology:
Sycosis occurs only in males after puberty
and commonly involves the follicles of the
beard.
the infecting organism is staphylococcal
aureus.
Sycosis

68. Clinical features:
It is an oedematous red follicular
papule or pustule around the hair.
The lesions are either discrete or
grouped on erythematous oedematous
base,especially on the upper lips and
below the angles of the jaw.
remission and relapses are common for
months or years.
Sycosis

72. Treatment:
Local antibiotics and in the nasal
vestibule also.
in chronic cases systemic
antibiotics for 10‐14 days.
Sycosis

73. ERYTHRASMA

74. Erythrasma
Definition:
is a mild,localized superficial infection
of the skin caused by corynebacterium
Minutissimum.
:Etiology
Clinical infection may occur at any age but is
more common among adults than
children,diabetes may be a predisposing
factor.,obesity and warm humid climate are
predisposing factors also.

75. Clinical features:
It occurs most commonly in the
groins,axillae and the intergluteal and
submammary flexures,in the groins,it
affects the area in contact with the scrotum.
the patches are of irregular shape and
sharply marginated,at first red but later
becoming brown, new lesions are smooth
but older lesions tend to be finely wrinkled
or scaly.

79. D.D. of erythrasma :
Intertrigo: Frictional dematitis.
Tinea cruris.
Flexural psoriasis.
Seborrhoeic dermatitis

80. Fluorescence under wood’s light:
Coral red fluorescence with wood’s light
strongly suggest erythrasma.
Treatment:
Erythrasma responds well to most topically
applied azole antifungal agents such as
clotrimazole and miconazole(although it is
a bacterial infection) for two weeks. For
more extensive lesions erythromycin is
probably the most effective approach,
alternatives include topical fucidin and oral
tetracycline.