Staphylococcal and Streptococcal Skin Infections
Session 8: Staphylococcal and Streptococcal Skin Infections
Total Session Time: 120 minutes
Pre-requisites
Students Learning Tasks
By the end of this session students are expected to be able to:
signs and symptoms)
and streptococcal diseases
Resources Needed:
SESSION OVERVIEW
|Step |Time |Activity/ |Content |
| | |Method | |
|1 |5 minutes |Presentation |Introduction, Learning Tasks |
|2 | 30 minutes|Presentation |Impetigo |
|3 |25 minutes |Presentation |Folliculitis |
|4 |20 minutes |Presentation |Farunculosis |
|5 |15 minutes |Presentation |Erysipelas |
|6 |10 minutes |Presentation |Cellulitis |
|8 |10 minutes |Presentation |Key Points |
| 7|5 minutes |Presentation |Evaluation |
SESSION CONTENTS
STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning tasks and clarify
ASK students if they have any questions before continuing
STEP 2: Impetigo (30 minutes)
o Impetigo is a superficial skin infection with crusting or bullae
caused by Streptococci, Staphylococci, or both.
o Impetigo is commonly caused by Staphylococcus aureus
o It affects the subcorneal layer of the epidermis with
characteristic honey-colored serous crusts. Ecthyma is an
ulcerative form of impetigo
o Impetigo commonly occurs in school children, usually starting on
the face, especially around the mouth or nose
o Impetigo may be bullous or nonbullous
impetigo and the cause of all bullous impetigo
staphylococci
o Nonbullous impetigo typically manifests as clusters of vesicles or
pustules that rupture and develop a honey-colored crust (exudate
from the lesion base) over the lesions
o Bullous impetigo is similar except that vesicles typically enlarge
rapidly to form bullae. The bullae burst and expose larger bases,
which become covered with honey-colored varnish or crust
o Ecthyma is characterized by small, purulent, shallow, punched-out
ulcers with thick, brown-black crusts and surrounding erythema
o Impetigo and ecthyma cause mild pain or discomfort
o Pruritus is common, scratching may spread infection, inoculating
adjacent and nonadjacent skin
o Remove crusts
o Wet dressings with;
o Topical therapy (Mupirocin 2%, Fusidic acid, Retapamulin
o Systemic antibiotics (if systemic symptoms e.g. pyrexia are
present)
STEP 3: Folliculitis (25 minutes)
o It is the inflammation of the hair follicle which may be caused by
bacteria, fungi, viruses or parasites.
o Bacterial folliculitis is usually caused by Staphylococcus aureus
and occasionally Pseudomonas aeruginosa
o Mild pain, pruritus, or irritation
o Superficial pustule or inflammatory nodule surrounding a hair
follicle
o Infected hairs easily fall out or are removed, but new papules
tend to develop
o Deep follicular inflammation often occurs in the bearded areas of
the face (Sycosis barbae)
o Avoiding suspected irritants
o Antiseptics
o Topical antibiotics (Neomycin, gentamycin, tetracyclines or
mupirocin)
o Systemic antibiotics (in systemic manifestations)
STEP 4: Furunculosis (20 minutes)
o Farunculosis is deep follicular infection that starts as a firm
red nodule which rapidly becomes painful and fluctuant in a few
days
o Furunculosis form furuncles (or boils) that are skin abscesses
caused by staphylococcal infection.
o Furuncles involve a hair follicle and surrounding tissue
o A cluster of furuncles forms a carbuncle. Carbuncles are clusters
of furuncles connected subcutaneously, causing deeper suppuration
and scarring.
o Furuncles are common on the neck, breasts, face, and buttocks
o They are uncomfortable and may be painful when closely attached to
underlying structures (e.g., on the nose, ear, or fingers)
o Appearance is a nodule or pustule that discharges necrotic tissue
and sanguineous pus. Carbuncles may be accompanied by fever and
prostration
o Usually resolves spontaneously, but improved by placing hot
compresses over the boil until it breaks
o Incision and drainage
o Antibiotics (those effective against MRSA)
STEP 5: Erysipelas (15 minutes)
o Erysipelas is a bacterial infection of upper half of dermis with
lymphatic vessel involvement, caused by Group A β-haemolytic
Streptococci (rarely by Group C, G and B)
o The disease occurs most frequently on the legs and face
o Erysipelas begins as a small break in the skin or umbilical stump
(infants)
o The affected area has growing redness, accompanied by high fever
and pains
o Erysipelas is characterized clinically by;
margins
o Rest
o Lifting affected part
o Antiseptics
o Topical antibiotics
o Systemic antibiotics
o In recurrent erysipelas treatment should be prolonged (10 to 14
days)
STEP 6: Cellulitis (10 minutes)
o Cellulitis is acute bacterial infection of the skin and
subcutaneous tissue most often caused by streptococci (S.
pyogenes) or staphylococci (S. aureus)
o Cellulitis is a deep inflammation and involves lower half of
dermis and subcutaneous tissue
o Cellulitis differ from erysipelas by;
systemic symptoms
o Pain, warmth, rapidly spreading erythema, and edema
o Fever may occur
o Regional lymph nodes may enlarge in more serious infections
o Immobilization
o Limb elevation
o Nonsteroidal anti-inflammatory Drugs (NSAIDs)
o Systemic antibiotics
STEP 7: Key Points (10 minutes)
bullous and nonbullous impetigo
potentiated by perspiration, trauma, friction, and occlusion of the
skin
effectively treated with clindamycin
discharges necrotic tissue and sanguineous pus, particularly on the
neck, breasts, face, or buttocks. Connected furucles are called
carbuncles.
lymphatic vessel involvement, caused by Group A β-haemolytic
Streptococci
and S. aureus.
STEP 8: Evaluation (5 minutes)
skin infection?
References
Hugo and Russell (2011), Pharmaceutical Microbiology 8th Edition, Willey-
Blackwel publications
Karen C. Carroll et al (2013); Jawetz, Melnick and Adelberg’s Medical
Microbiology 26th Ed. McGraw Hill Co. Inc.
Greenwood et al (2012); Medical Microbiology, 18th edition Churchill
Livingstone
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