Herpes Simplex and Pityriasis Alba

July 1, 2002

For 3 days, a 36-year-old woman has had a painful rash on the dominant lefthand. She had noticed a tingling sensation before the lesions erupted. Thepatient is otherwise healthy and takes no medications. She is a teacher.

Case 1:
For 3 days, a 36-year-old woman has had a painful rash on the dominant lefthand. She had noticed a tingling sensation before the lesions erupted. Thepatient is otherwise healthy and takes no medications. She is a teacher.

What does this look like to you?

A.

Hand-foot-and-mouth disease.

B.

Herpes simplex.

C.

Herpes zoster.

D.

Contact dermatitis.

E.

Impetigo.

You offer which of the following?

F.

Oral antiviral therapy for herpes simplex virus infection.

G.

Oral antiviral therapy for varicella-zoster virus infection.

H.

A corticosteroid cream.

I.

A 1-week course of cephalexin.

J.

Reassurance.

Case 2:
During the last few weeks, an asymptomatic, hypopigmented rash has developedon the shoulders of a 10-year-old boy. He has been spending a good dealof time in an outdoor swimming pool.

Which condition in the differential is the likely cause?

A.

Tinea versicolor.

B.

Vitiligo.

C.

Pityriasis rosea.

D.

Pityriasis alba.

E.

Nummular eczema.

Which of the following do you prescribe?

F.

An antifungal cream.

G.

A low-potency corticosteroid cream.

H.

A tapered course of prednisone.

I.

Moisturizers.

J.

Sunscreen.

Case 1: A culture grew herpes simplex virus (HSV) type 1,B, although nothing in the patient's history explainedhow she might have been exposed to the virus. Because ofhand to mouth contact, dentists, hygienists, and nursesare at particular risk for acquiring this self-limited infection.Most HSV infections are painful; patients also complain ofan itching or tingling sensation. Antiviral therapy, F,resolves the outbreak.

Herpes zoster is more extensive, since it generallyaffects the entire dermatome. Hand-foot-and-mouth diseaseinvolves both hands equally. Discrete, erythematouspapules typically do not develop in contact dermatitis.Impetigo usually presents with a pruritic, tender, vesiculopustulareruption that rapidly becomes crusty.

Case 2:Pityriasis alba, D--a postinflammatory hypopigmentation seen inpatients with atopy--is caused by low-grade eczema that can be precipitatedby the failure to use moisturizers and sunscreen and by an excessive amountof time in a pool. It is thought that the inordinate exposure to water strips theskin of its protective oils and incites a low-grade eczema.

The hypopigmented areas of pityriasis alba do not tan; therefore, theyare more noticeable against a background of sunburnt skin. Reassure patientsthat the loss of pigment is not permanent. Moisturizers, I, can be helpful. Theappearance of the affected area may improve more quickly when a moisturizeris applied in conjunction with a low-potency topical corticosteroid, G, andregular use of a sunscreen, J.

Tinea versicolor, nummular eczema, and pityriasis rosea are usually morescaly; the latter condition features more erythema than is noted in pityriasisalba. Vitiligo is characterized by depigmentation, not hypopigmentation; therefore,the contrast in skin color is more dramatic than the discoloration seenin this patient.

Case 3:
A 46-year-old man is bothered by aprogressively worsening rash on hisleft calf that first erupted severalmonths earlier. The intermittentlypruritic eruption occasionally appearsto begin to heal then, inexplicably,flares again. Over-the-counter topicalantifungal and corticosteroid creamshave not been effective. The patientowns a cat.

What do you suspect?

A.

Urticaria.

B.

Tinea corporis.

C.

Fixed drug eruption.

D.

Nummular eczema.

E.

Contact dermatitis.

What is your first step?

F.

Perform a fungal culture.

G.

Perform patch tests.

H.

Perform a potassium hydroxideevaluation.

I.

Have the cat examined by aveterinarian.

J.

Perform a skin biopsy.

Case 4:A 41-year-old man's wife was concerned about the whitespots that developed on her husband's neck during thelast week. Because the lesions were asymptomatic, the patientwas unaware of their presence. The patient is a constructionworker; he takes no medications.

Can you identify this condition?

A.

Tinea versicolor.

B.

Pityriasis rosea.

C.

Drug eruption.

D.

Urticaria.

E.

Mycosis fungoides.

What action do you take?

F.

Prescribe a corticosteroid cream.

G.

Prescribe a systemic antifungal agent.

H.

Prescribe a tapered dosage of prednisone.

I.

Prescribe an antifungal cream.

J.

Offer reassurance.

Case 3: The lesion's raised, serpiginous border heightenedsuspicion of a fungal infection. Tinea corporis, B, wasconfirmed by a potassium hydroxide (KOH) evaluation,H. A fungal culture can establish the diagnosis as well,but a KOH examination is more expedient. Most likely,the patient's pet cat was the source of the dermatophyte.Over-the-counter (OTC) corticosteroid preparationscan exacerbate dermatophyte infections, since their antiinflammatoryproperties mask the infection. Some OTCantifungal creams are not especially effective againstdermatophytes; therefore, a lack of response does notnecessarily rule out this type of fungal infection.

Contact dermatitis and urticaria last for days, notmonths. A fixed drug eruption typically is more painfulthan pruritic; the usual flare upon rechallenge with the offendingagent, which is a hallmark of this drug hypersensitivity,was absent from this patient's history. Nummulareczema can be persistent but generally does not wax andwane at a single site.

A systemic antifungal agent was prescribed for thispatient's fairly extensive tinea corporis; a topical preparationis another effective option. He was advised to havehis pet evaluated and treated as well, I.

Case 4: This is tinea versicolor, A, ayeast infection that can present ashyperpigmented or hypopigmentedmacules with a fine scale. A potassiumhydroxide (KOH) evaluation of ascraping of scale confirmed the diagnosis.The difference in the skin pigmentationof the affected area ascompared with the surrounding noninvolvedskin is usually more apparentin the summer; it is thought thatthe more humid environment encouragesthe yeast to flourish.

Urticaria typically does not lastfor days. A drug eruption was notsupported by the history; pityriasisrosea was ruled out by the KOH examination.The rash of mycosis fungoideshas a poikilodermatic appearancewith atrophy and telangiectasia.

Although tinea versicolor respondsto both topical, I, and oral, G,antifungal therapy, topical agents arenot always as effective or as cosmetically acceptable as oral therapy. It has beensuggested that the relapse rate following systemic therapy is lower because theantifungal antibiotic penetrates the sebaceous follicle more efficiently and eradicatesthe yeast. Inform patients that recurrences are not uncommon, regardlessof the mode of treatment.

Case 5:During the last few weeks, a pruritic rash developed onthe extremities of an 8-year-old girl. Her only medication isa nonsedating antihistamine for seasonal allergies. The patienthas several pet cats and a dog. The mother reportedno change in the child's bathing or moisturizing habits.

What are you looking at here?

A.

Follicular eczema.

B.

Dermatophyte infection.

C.

Urticaria.

D.

Scabies.

E.

Contact dermatitis.

Your management strategy includes which of thefollowing?

F.

Recommend a change in soap and bathing habits.

G.

Recommend use of a moisturizer.

H.

Prescribe a topical antifungal agent.

I.

Prescribe an oral antifungal agent.

J.

Prescribe a topical corticosteroid.

Case 6:A 32-year-old man seeks evaluation ofa slightly pruritic rash on the trunkand extremities of 2 days' duration.He has had an upper respiratory tractinfection for a week. Four days earlier,he received an antibiotic at a walkinclinic; he does not recall the nameof the drug.

What are you looking at here?

A.

A viral exanthem.

B.

An adverse drug reaction.

C.

Erythema multiforme.

D.

Psoriasis.

E.

Contact dermatitis.

How do you proceed?

F.

Obtain the name of the drug from the clinic.

G.

Discontinue the antibiotic.

H.

Prescribe systemic corticosteroids.

I.

Order blood analysis.

J.

Perform a skin biopsy.

Case 5:

The history of seasonal allergies suggested

folliculareczema

,

A

--a clinical variant of atopic dermatitis thatmanifests with erythematous, follicular papules on thetrunk and/or extremities. Because the patient could haveacquired a dermatophyte from one of her pets, a fungalinfection was included in the differential; it was ruled outby the eruption's appearance and a negative potassiumhydroxide examination. Multiple discrete lesions can arisein areas that are shaved; however, this 8-year-old doesnot shave. Nothing in the history supported a contact dermatitis.Urticarial wheals are generally more widespreadand can be transient; they may erupt and resolve at differentsites.The limited rash, its absence on the child's hands,and the comparatively mild pruritus that did not disturbthe patient's sleep argued against scabies, which is neitherfollicular nor confined to the extremities. If in doubt, a mineraloil scabies examination may be performed.Mild soaps, short and less frequent baths,

F

, and thegenerous use of moisturizers,

G

, are recommended forpatients with an atopic diathesis who have folliculareczema. A topical corticosteroid,

J

, can be helpful as well.

Case 6:

You can never have too much information; identifying the antibiotic aspenicillin,

F

, helped confirm the diagnosis of an

adverse drug reaction

,

B

,which had been suggested by the appearance and the history. Any drug hasthe potential to cause an adverse reaction, but the incidence is higher withsome agents, such as penicillin. Most drug reactions peak in 3 to 5 days; mildreactive rashes resolve uneventfully. Antihistamines can ameliorate the pruritus.Reserve systemic corticosteroids,

H

, for severe reactions.Viral exanthems are relatively rare in adults. Erythema multiformelesions are discrete, usually painful, and have a predilection for palms andsoles. More diffuse and more pruritic lesions are seen in contact dermatitis.Guttate psoriasis that may follow an upper respiratory tract infection featuresdiscrete, small, scaly papules.