Impetigo

Ans. is ‘d’ i.e., Bullous impetigo

• Impetigo is divided into two types :‑

i)          Non-bullous impetigo (Impetigo contagiosum) :- Caused by staphylococcus aureus and streptococcus pyogenes.

ii)        Bullous impetigo :- Caused by staphylococcus aureus.

Ans. is ‘a’ i.e., Group A beta hemolytic streptococci 

C i.e. Produce scar on healing 

B i.e. Impetigo contagiosa

B i.e. Staphylococcus

B i.e. Impetigo

A. i.e. Contageous, B. i.e. Bacterial infection

Impetigo (Pyoderma)

It is a contiguous, superficial pyogenic infection of skin. Pyodermas are infections in epidermis, just below the stratum corneum or in hiar follicles. Two main clinical forms are

1. Bullous impetigo accepted as staphylococcal disease (by S. aureus) mostly.
2. Nonbulous impetigo (or impetigo contagiosa or Tilbury Fox) may be cause by Staphylococcus aureus (most

common); by group A-I3 haemolytic streptococci (mainly in developing nations) or by both.

Pre school and young school age children are most commoly affectedQ. Although over-crowding (living in barracks), poor hygiene and existing skin disease especially scabies, predispose to infection. It most commonly affects children and is most common bacterial infection of childrenQ. It occurs in all age including adults and neonates (called pemphigus neonatorum). It spread by close cantact (contageous).

In nonbulous impetigo, the initial lesion is a very thin walled vesicle on an erythematous base which ruptures so rapidly that its seldom seen. The exuding serum dries to form yellowish brown (golden or honey coloured) crustsQ, which are usually thicker and dirtier in strptococal form. Gradual, irregular, peripheral extension occurs without central healing. Multiple lesions may coalesce, crusts eventually dry and separate to leave erythema, which fades without scarring. Lesions are usually not painful, heals without scarringQ, no fever and patient is not ill. Characteristic feature is honey clored crust and neutrophils beneath stratumQ corneum.

–   Face (esp around nose and mouth) and limbs are most commonly affected but scalp (in tinea capitis) and other body parts (in atopic dermatitis and scabies) are involved also. Lesions cure spontaneously in 2-3 weeks. In Bullous impetigo, the bullae are less rapidly ruptured, are much larger (1-2cm) and persist for 2-3 days. After rupture thin, flat brownish crusts are formed. Central healing and peripheral extension may give rise to circinate lesions.

Streptococal impetigo may 1/ t post streptococcal acute glomerulonephritis (AGN)Q, Scarlet fever, urticaria and erythema multiforme complications. Rheumatic fever is not a complication of streptococcal impetigoQ. Treatment include oral dicloxacillin or cephalexinQ and topical mupirocin or sodium fusidateQ.

A i.e. Impetigo contagiosa; B i.e. Ecthyma; C i.e. Furncle 

–  Pyoderma gangrenosum (PG) is non infectious neutrophilic dermatosis commonly associated with underlying systemic disese like UC, Chrons etc. Pyostomatitis vegetans, malignant pyoderma, superficial vegetative granulomatous pyoderma, ulcerative/pustular/bullous erruptions of UC are variants of PG.

Pyoderma faciale also k/a rosacea fulminans or rosacea conglobata occurs mainly in adult women (in 20s) and is characterized by sudden, severe erruption of confluent papules, nodules, pustules, cystic swellings which may be interconnected by draining sinuses usually confined to face, involving checks, chin, nose & forehead within a background of diffuse facial erythema. Comedones are usually absent or inconspicuous, as are other features of acne vulgaris or rosacea (& yet unclear whether this is a variant of these or a seperate entity). Some cases may develop during pregnnacy or medication (interferon a-2B & ribavirin therapy for hepatitis C)

Impetigo herpetiformis is variant of pustular psoriasisQ attributed to hormonal alterations during pregnancy (generally during 3^rd trimester)Q. Absence of positive family history, abrupt resolution of symptoms at delivery and a tendency to only recur during subsequent pregnancies distinguish this from generalized pustular psoriasis. Impetigo contagiosaQ, bullous impetigo, ecthymaQ, botryomycosis, superficial folliculitis (follicular or Bockhart impetigo), folliculitis (sycosis barbae)Q, furncle (boil)Q, carbuncle, blistering distal dactylitis and paronychia are superficial primary pyodermas caused by staph.aureus. Whereas, impetigo, ecthyma, blistering distal dactylitis (in nonintertriginous skin) and intertrigo, vulvovaginitis & perianal cellulitis (in inter triginous skin) are superficial primary pyodermas caused by group A streptococci. Pyoderma gangrenosum, pyoderma faciale & impetigo herpetiformis are not pyodermasQ.

Trichomycosis axillaris & pubis is a bacterial (aerobic corynebacterium) not fungal infection of hair shaft. Erythrasma is superficial bacterial infection of skin caused by corynebacterium minutissimumQ.

C i.e. Imetigo contagiosa

Piedra is a fungal infection of hair. Pyoderma gangrenosum is a rare, serious ulcerative disorder that is often d/t serious underlying systemic disease eg ulcerative colitis, chron’s disease, rheumatoid arthritis or myeloma etc. Impetigo herpetiformis is the synonym of generalized pustular psoriasis of pregnancy.

Ans. A i.e. Staphylococcus aureus

• SSSS (Staphylococcal scalded skin syndrome),
• Bullous impetigo/Impetigo contagiosa,
• Furuncles/ Boils,
• Sycosis barbae and Sycosis nuchae

Ans. is ‘b’ i.e., Staphylococcus

• Impetigo is divided into two types :‑

1. Non-bullous impetigo (Impetigo contagiosum) :- Caused by staphylococcus aureus and streptococcus pyogenes.
2. Bullous impetigo :- Caused by staphylococcus aureus.

Ans. is ‘a’ i.e., Dicloxacillin

• Treatment of impetigo is either dicloxacillin or cephalexin can be given at a dose of 250 mg four times daily for 10 days.
• Topical mupirocin ointment is also effective.

Ans. is ‘b’ i.e., Bullous impetigo

I am not able to understand this question. As most of the isolates of virulent staph aureus produce golden yellow pigment in culture. It is not disease specific.

In Bullous impetigo, there may be postinflammatory pigmentation, especially in dark-skinned patients (But this is not due to pigment produced by staph aureus. Pigment is produced in culture).

Among the given options a & c are not caused by staph aureus. So, I will go for option b.

Ans. is ‘b’ i.e., Staphylococcus

Impetigo

• Impetigo is a highly contagious, Gram-positive bacterial infection of superficial layer of epidermis. Impetigo occurs in Two forms : –
• Non – bullous impetigo (Impetigo contagiosa)
• It is the most common bacterial infection of children (occurs mainly in children in contrast to Bullous impetigo which occurs in infants). It is caused by both staphylococcus aureus and hemolytic group A streptococcus (Str. pyogens), though it is mostly caused by staph aureus. Most commonly occurs on face, i.e., around nose & mouth; and exposed parts, i.e., arms, legs. Presents erythematous macule/papule which changes into vesicle which soon ruptures with formation of crusting. Crust has characteristic features : –

1. Honey-yellow colour in streptococcal impetigo.
2. Waxy in staphylococcal impetigo.

• Lesion heal without scarring. Mucous membrane involvement is rare. Lymphadenopathy is common

Bullous impetigo

• It is caused by staphylococcus aureus most often phage type 71. It usually occurs in infants and manifests as vesicle that develop into bulla and later a pustule without any surrounding erythema. It mainly occurs on face. Mucous membrane may be involved (in contrast to impetigo contigiosa). Lymphadenopathy is rare.

Ans. is `d’ i.e., All of the above

Niko!sky’s sign is seen in ‑

• Pemphigus
• Toxic epidermal necrolysis
• Bullous impetigo
• Steven jonson syndrome
• Staphylococcus scalded skin syndrome
• HSV & VZV infection
• Epidermolysis bullosa                                 
• Malignancy (leukemia)
• Mycosis fungoides
• Bullous lichen planus

Ans. is ‘b’ i.e., Staphylococcus

Impetigo

• Impetigo is a highly contagious, Gram-positive bacterial infection of superficial layer of epidermis. Impetigo occurs in Two forms : ‑

1. Non – bullous impetigo (Impetigo contagiosa)

• It is the most common bacterial infection of children (occurs mainly in children in contrast to Bullous impetigo which occurs in infants). It is caused by both staphylococcus aureus and hemolytic group A streptococcus (Str. pyogens), though it is mostly caused by staph aureus. Most commonly occurs on face, i.e., around nose & mouth; and exposed parts, i.e., arms, legs. Presents erythematous macule/papule which changes into vesicle which soon ruptures with formation of crusting. Crust has characteristic features : –

1. Honey-yellow colour in streptococcal impetigo.
2. Waxy in staphylococcal impetigo.

• Lesion heal without scarring. Mucous membrane involvement is rare. Lymphadenopathy is common

2. Bullous impetigo

• It is caused by staphylococcus aureus most often phage type 71. It usually occurs in infants and manifests as vesicle that develop into bulla and later a pustule without any surrounding erythema. It mainly occurs on face. Mucous membrane may be involved (in contrast to impetigo contigiosa). Lymphadenopathy is rare.