Multimicrobial Skin Infection and Staphylococcal Infection

Case 1:
Painful erosions developed on the sole of a 14-year-old girl's foot several weeksearlier. Within the last few days, the condition has spread to the other sole.The patient is otherwise healthy and takes no medications. She enjoys playingsoccer and has no history of trauma.

Do you recognize this condition?

A. Tinea pedis.
B. Dyshidrosis.
C. Staphylococcal infection.
D. Streptococcal infection.
E. Candidiasis.

Your treatment plan includes . . .

F.

An oral cephalosporin.

G.

An imidazole antifungal cream.

H.

An allylamine antifungal cream.

I.

Mupirocin cream.

J.

A topical corticosteroid cream.

Case 2:
After a basketball game 1 week earlier,a 10-year-old boy was bothered by ablister on his heel. Subsequently, thelesion became sore and red. Duringthe last 2 days, an asymptomatic,rough rash has erupted over most ofthe child's body. He has a low-gradefever and has been taking ibuprofenfor the pain in his heel.

What are you looking at here?

A. An adverse reaction to theibuprofen.
B. Urticaria.
C. Scarlatiniform eruption.
D. Infectious mononucleosis.
E. Toxic shock syndrome.

Your initial strategy is to . . .

F. Stop the ibuprofen.
G. Perform a monospot test.
H. Prescribe a systemic corticosteroid.
I. Prescribe an antistreptococcalantibiotic.
J. Prescribe an antistaphylococcalantibiotic.

Case 1: A bacterial culture grew out both Staphylococcus aureus, C, andStreptococcus viridans,D. An oral cephalosporin, F, cleared the infections;mupirocin cream, I, also is effective in this setting. The patient was told tomake sure her sneakers are clean.

Tinea pedis usually is pruritic, not erosive. Typically, candidal foot infectionsdo not occur in immunocompetent persons. Dyshidrosis generally manifestsas a pruritic, vesicular eruption, not painful erosions.

Case 2: Staphylococcal infections can produce a scarlatiniformeruption, C, as seen in this patient. The absenceof pharyngitis ruled out both a streptococcal infection andinfectious mononucleosis. Although an adverse reactionto ibuprofen is in the differential, the blister suggested adifferent cause. Urticaria is generally pruritic and manifestsas wheals, not the rough rash seen here. Erythrodermaand desquamation of the palms and soles are seenin patients with toxic shock syndrome, who are usuallymuch more severely ill than this patient.

A short course of a first-generation cephalosporin, J,relieved all the symptoms.

Case 3:
A 5-year-old girl with atopic dermatitisis brought to your office with a 4-dayhistory of what the mother describesas "itchy eczema" on her legs.

What are your thoughts aboutthe cause of the rash?

A. Atopic dermatitis flare.
B. Impetigo.
C. Herpes simplex.
D. Molluscum contagiosum.
E. Candidiasis.

Which topical therapy do youoffer?

F. A corticosteroid cream.
G. Mupirocin.
H. An imidazole antifungal cream.
I. Salicylic acid to be applied toeach lesion.
J. Acyclovir ointment.

Case 4:
Twenty years after an asymptomatic growth erupted on his shin, a 77-year-oldman seeks medical evaluation of the slowly enlarging lesion.

What do you suspect?

A. Seborrheic keratosis.
B. Basal cell carcinoma.
C. Melanoma.
D.Venous angioma.
E. Blue nevus.

Which course of action do you pursue?

F. Perform a shave biopsy.
G. Perform a punch biopsy.
H. Perform an incisional biopsy.
I. Perform an excisional biopsy.
J. Offer reassurance.

Case 3: The sudden onset of thisoozing, crusted eruption suggestedmore than just a flare of eczema.The patient's persistent scratchinghad caused a secondary staphylococcalinfection, impetigo,B. Topicalmupirocin, G, resolved the infection.

Herpes simplex occurs in personswith atopy; however, the eruptionusually is vesicular and painful.Candidiasis can mimic impetigo, butit is seen much less frequently. Molluscumcontagiosum features umbilicatedpapules.

Case 4: The lesion's pigmentation and general appearance suggested apossible skin cancer. A punch biopsy, G, confirmed the diagnosis of basal cellcarcinoma,B. Because of the possibility of melanoma, the biopsy specimenneeds to include the base of the tumor; therefore, choices H and I are appropriateas well. A deep shave biopsy, F, may be adequate.

A bluish lesion is not typical of seborrheic keratoses. The appearance of venousangiomas can be deceptive, but they usually look more vascular than thislesion. Blue nevi may be nodular; rarely, they undergo malignant degeneration.

This basal cell carcinoma-the only such lesion on this patient-was surgicallyremoved without complications.

Case 5:
Eight months ago, a short, tapereddose of prednisone resolved pityriasisrosea in this patient. Now, the 14-year-old boy presents with a similar,mildly pruritic rash on his trunk. Heis otherwise healthy, having fully recoveredfrom an upper respiratorytract infection 3 or 4 weeks ago.Ten days ago, he returned from aclass camping trip. The patient takesno medication.

Which of the following wouldyou consider . . .

A. A recurrence of the pityriasis rosea.
B. Guttate psoriasis.
C. Tinea corporis.
D. Reaction to an insect bite.
E. Contact dermatitis.

Case 6: A 15-year-old girl seeks treatment of asymptomatic whitestreaks that appeared on her trunk and thighs a fewmonths earlier. The patient is otherwise healthy, takes nomedications, and has not had any significant weightchanges in the last year.

What is the likely diagnosis?

A. Tinea versicolor.
B. Pityriasis alba.
C. Vitiligo.
D. Striae.
E. Scars from physical abuse.

Your initial course of action is to . . .

F. Contact the local social services department.
G. Prescribe tretinoin cream.
H. Prescribe topical corticosteroid cream.
I. Prescribe oral ketoconazole.
J. Offer reassurance.

Case 5:Pityriasis rosea,A, can occurmore than once, and often developsafter a recent upper respiratory tractinfection. The diagnosis 8 monthsago was correct. Guttate psoriasis isusually seen on the legs and doesnot respond to a tapering course ofprednisone. Ringworm in an otherwisehealthy person is not as extensiveas this patient's eruption. Insectbites and contact dermatitis typicallyare not flat, scaly patches that areconfined to the trunk.

Another course of tapered-doseprednisone resolved the rash. Thepatient has not had a recurrence for2 years.

Case 6:Pubertal striae,D, developed as a result of rapid growth. A severalmonthcourse of tretinoin cream, G, can improve the appearance of these unsightlylesions. Striae usually are found on the back, around the breasts andthighs of adolescent girls and young women, and on the upper arms and backof adolescent boys and men.

Tinea versicolor features discrete hypopigmented or hyperpigmentedmacules that typically appear on the trunk. Pityriasis alba manifests in personswith atopy as ill-defined, hypopigmented patches. The patches of vitiligo aredepigmented. Traumatic injuries generally have a linear or irregular scarringpattern that reflects the source of the injury.