35-year-old Swiss man, living in Africa, is home on a visit, and develops swelling in his groin.
Is this painful?
Yes, if I press on the spot.
Tenderness to touch helps limit the differential diagnosis a bit.
How long have you had these lesions?
About a week.
The time course of a disease often gives clues to the etiology.
Did you have a sore in the genital area before the swelling started?
No, not that I noticed. Of course, once in a while, one gets a little tear, but I can't remember.
The presence or absence of a genital ulcer also helps to limit the differential diagnosis. On the other hand, the patient may have overlooked a small or hidden lesion.
Have you had lesions anywhere else?
You should still perform a total skin examination. The patient may not have noticed something.
Have you had unprotected sexual intercourse?
I always use a condom, but 2 months ago in Mombassa, I was with a prostitute and didn't have one handy. I could kick myself in the ass.
Unilateral lymph node swelling should always suggest an sexually transmitted disease.
What kind of work do you do?
I manage a hotel in Kenya.
It is always good to have a view of your patient's life and work, although in this case, it does not help a great deal.
Choose the right efflorescences:
Hives are transient lesions.
There is redness of the skin, but that is not the problem.
Tumor just means swelling, so it is correct.
The patient has subcutaneous nodules, enlarged lymph nodes.
Choose the right diagnosis:
No evidence for a chancre, and the lymphadenopathy in syphilis is usually painless.
Erysipelas can also have lymphadenopathy, but the preceding circumscribed warm erythema is not described.
This disease is caused by Chlamydia trachomatis Serotypes L1-L3. The initial small genital ulcer is often overlooked.
The is no evidence for a cutaneous lymphoma. A malignant lymphoma could present with unilateral inguinal lymphadenopathy, but should not be your first diagnosis.
Way off!! Erythema nodosum is a panniculitis, presenting with bruise-like lesions on the shins.
Choose the right therapy(ies):
This is one treatment for recurrent herpes simplex.
Not an effective regimen.
This is not a fungal toenail infection.
This is the recommended approach.
This antibiotic only weakly covers chlamydia. The massive dose does not correct the problem.