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Case 54

15-year-old boy who noticed annular lesions on back of foot after a trip to India

I think something was there during the trip but I am not sure.

It is important to know if the lesions were present before the trip or not. Otherwise one must consider those infections endemic to the part of the world the patient visited.

No. My dad had terrible eczema but it cleared up during the trip.

Did our patient really pick up an infection in India? Hard to say; let's keep asking.

No, they do not itch. It just bothers me that no one knows what they are.

Always ask about accompanying symptoms such as pain, pruritus, burning or loss of sensation.

I used to have eczema.

Good question. Maybe he had exactly this problem before or maybe he has atopy and a tendency to have skin problems.

No, just the shots before we left.

Always think about drug reactions. A fixed drug reaction can be localized like this lesion, but it looks completely different.

Sure, I play soccer and I'm always getting kicked there?

This question causes more trouble than most others. Almost everyone always gives a positive history of trauma. It is much easier just to check on the physical examination.


Not a wise question. This has zero features of a sexually transmitted disease and you run the risk of loosing the patient's trust and respect.

Choose the right efflorescences:

No scales are seen. Sometimes more diffuse scaling can obscure a primary lesion.

Lichenification is caused by persistent rubbing of the skin and features exaggerated skin markings.

Correct. There are many small papules arranged in annular pattern.

There is no loss of skin substance here.

Choose the right diagnosis:

Inexperienced observers often call this “ringworm” and often treat it as such. But there are grouped papules, no scale and a negative KOH examination. Learn that this lesion is NOT a fungal infection!

Urticaria is a transient disease, and itches.

This common disease is often on the back of the hand or foot in children and teenagers, so this case is classic. The cause is unknown, but most resolve spontaneously. In adults with multiple lesions, exclude diabetes mellitus.

The incubation period for leprosy is much longer than this history. Just not possible!

Choose the right therapy(ies):

Often an effective and quick way to eliminate the lesions. May heal with atrophy.

Most go away spontaneously; thus treatment of choice.

If you are unsure, a biopsy confirms the answer and there are many reports of the disease disappearing after a small biopsy.

Totally unnecessary and not helpful.

This is the most effective therapy, but can also lead to atrophy. Be careful with the underlying vessels and tendons!

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