Simple cases
Case 54
15-year-old boy who noticed annular lesions on back of foot after a trip to India
History
How long after you got back did you notice these spots?
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.
Does anyone else on the trip or in the family have similar changes?
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.
Do the lesions bother you?
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.
Do you have any other skin problems?
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.
Did you have to take any medications on the trip?
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.
Did you have any trauma to your foot?
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.
Have you had unprotected sexual intercourse?
No.
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.
Lesion
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.
Diagnosis
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!
Therapy
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!
Test
The following questions are related to the current case. Try to solve them.
