Livedo Reticularis and Contact Dermatitis to Poison Ivy

Case 1:
A network of purplish pink lesions recently developed on a 28-year-old woman'sarms and legs. The asymptomatic rash becomes more prominent with exposureto cold. The patient denies fever, aches, arthralgias, oral erosions, chestpain, and photosensitivity.

Which of the disorders in the differential is the likely diagnosis?

A.

Erythema ab igne.

B.

Livedo reticularis.

C.

Cutis marmorata.

D.

Raynaud phenomenon.

Which of the following disorder(s) is associated with this patient's skincondition?

E.

Hepatitis C.

F.

Lupus erythematosus.

G.

Pancreatitis.

H.

Minocycline hypersensitivity.

I.

Syphilis.

Case 1:Livedo reticularis,B, is characterizedby a mottled pattern of reddishblue macules that are attributedto sluggish blood flow through thereticular blood vessels. The disorderis associated with a variety of conditions,including hepatitis C, E; lupuserythematosus, F; pancreatitis, G;minocycline hypersensitivity, H; andsyphilis, I.

Erythema ab igne is caused byprolonged exposure to a heat source,such as a hot water bottle; the initialerythema gives way to brown hyperpigmentationof the affected skin.The mottling of cutis marmorata,which is seen in neonates, is transientand can disappear when the skin iswarmed. In patients with Raynaudphenomenon, cold or emotional stimuli can produce ischemia of the toes and fingers that is oftenassociated with paresthesia and pain of the affected digits.

Although this patient's antinuclear antibody level was elevated, it fell short of the criterion for aconnective tissue disorder. She is being followed closely for additional signs of lupus erythematosusor other underlying disease.

Case 2:
A 44-year-old man presents with aprogressively worsening itchy lesionon the arm that has become a painful,draining plaque during the past 12days. An injection of methylprednisoloneacetate, oral ampicillin, and oraldiphenhydramine hydrochloridegiven in the emergency department1 week earlier failed to resolve thelesion. The patient is otherwisehealthy and enjoys doing yard work.

Can you identify the lesion?

A.

Poison ivy rash with secondarybacterial infection.

B.

Brown recluse spider bite.

C.

Black widow spider bite.

D.

Gram-positive bacterial cellulitis.

E.

Factitial dermatitis.

Your treatment plan includes . . .

F.

A second injection ofmethylprednisolone acetate.

G.

An injection of triamcinoloneacetonide.

H.

A different antibiotic, such ascephalexin.

I.

A systemic antifungal agent.

J.

A protective wrap placed over thearm to prevent exacerbation ofthe suspected self-inflicted lesion.

Case 2:

The patient had a contactdermatitis, most likely

poison ivy

, contractedwhile gardening, with a

secondarybacterial infection,

A.

Spiderbites and cellulitis are not initiallypruritic; the patient's history did notsupport a factitial dermatitis.The corticosteroid he receivedis more appropriate for chronic conditions,such as arthritis; methylprednisoloneacetate is not adequate therapyfor acute skin problems. Theprescribed antibiotic, oral ampicillin,did not cover the secondary staphylococcalinfection, which was provokedby intense scratching of the pruriticpoison ivy. Diphenhydramine hydrochloridecan ameliorate pruritus,but it plays no role in the treatment ofpoison ivy.Intramuscular triamcinoloneacetonide,

G,

and a cephalosporin,

H,

produced dramatic improvementwithin 2 days.

Case 3:
A 29-year-old woman has had asymptomatic red spots on her upper trunk for2 weeks. She complains that the lesions appear to be spreading. The patienttakes no medication and denies exposure to the sun.

What are you looking at here?

A.

Urticaria.

B.

Pityriasis rosea.

C.

Tinea versicolor.

D.

Drug eruption.

E.

Mycosis fungoides.

Which of the following do you offer the patient?

F.

Reassurance only.

G.

An antifungal cream.

H.

A systemic antifungal agent.

I.

A tapered dosage of prednisone.

J.

A corticosteroid cream.

Case 3:

A potassium hydroxide (KOH) examination of ascraping of fine scale from a lesion confirmed the diagnosisof

tinea versicolor,

C.

The variety of colors of the presentinglesions gives this yeast infection its name; maculesor patches may be hyperpigmented or hypopigmentedand manifest as white, pink, or brown lesions.Typically, urticaria lasts for hours, not days or weeks.Pityriasis rosea was ruled out by the KOH evaluation.The patient's history did not support a drug eruption. Mycosisfungoides' psoriasislike eruption with atrophy andtelangiectasia most commonly arises on the lower trunk,buttocks, and thighs; tinea versicolor is most prominenton the upper trunk. Vitiligo is often included in the differentialof black-skinned patients with hypopigmented tineaversicolor lesions; a KOH examination will confirm thefungal infection.Oral antifungal therapy,

H,

is often more effectivethan topical agents. Systemic drugs may be better able toeradicate the yeast and forestall recurrences, which arenot uncommon.

Case 4:
For several weeks, a 34-year-oldwoman has had a pruritic rash underher breasts. She also complains ofitching; slight redness; and scale inthe groin area, eyebrows, and nasolabialfolds. The patient has type 2diabetes mellitus, which is well controlledwith glipizide.

Which disorder in the differentialis the likely diagnosis?

A.

Seborrheic dermatitis.

B.

Psoriasis.

C.

Contact dermatitis.

D.

Diabetic dermopathy.

E.

Candidiasis.

What action do you take?

F.

Perform patch tests.

G.

Perform a potassium hydroxideevaluation.

H.

Examine the hands for nail pitting.

I.

Obtain a serum glucose level.

J.

Prescribe an over-the-counterantifungal powder.

Case 4:

A potassium hydroxide examination,

G,

ruled out a fungal infectionand thus supported the diagnosisof

seborrheic dermatitis,

A.

Thiserythematous, scaling rash arises in aseborrheic distribution, which involvesthe eyebrows, eyelids, nasolabialfolds, ears, scalp, mid chest and, lesscommonly, the axillae, umbilicus, andgroin. Psoriasis can occur secondaryto the inflammation caused by seborrhea(the Koebner phenomenon) butwas unlikely here because of the absenceof nail pitting,

H,

or other characteristicchanges. The distributionwas not typical of a contact dermatitis,which is usually seen on exposedareas and is much more pruritic, or a

Candida

infection, which is morecrusty and features satellite lesions.Diabetic dermopathy is characterizedby brown macules that overliethe shins and is often seen in personswith diabetes. This patient's historyof diabetes was not relevant to her cutaneousdisorder.