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Simple cases
Case 58
64-year-old man presents with lesions which suddenly appeared on his buttocks
History
How did you notice these lesions on your buttocks?
I noticing them taking a shower; the skin felt bumpy back there.
The lesions don't seem to be bothering the patient much, but let's explore further.
Do they itch?
Yes, from time to time.
Important question. The answer can help with the differential diagnostic process.
Have you ever had anything like this before?
I think so. I didn't go to the doctor.
It is always good to know if you are dealing with an acute or chronic problem. Unfortunately, here the patient is not sure.
What kind of work do you do?
I am in informatics.
This question might sound silly at first, but it gives you lots of information. Here we learn that the patient sits a great deal, so perhaps his skin problem is triggered by pressure and occlusion.
Have you had trouble with fever blisters?
Yes, I get fever blisters once in awhile, especially when I am really exhausted.
Good question, which helps in the differential diagnosis.
Are you otherwise healthy?
I think so. I don't go to the doctor much.
The patient feels well, but might have an underlying disease, since he hasn't been checked closely.
Do any diseases run in your family?
No.
Most people know if diabetes mellitus, cancer or heart problems are common in their family. When it comes to skin diseases, this question often just causes confusion, as psoriasis and atopic dermatitis, for example, are confused.
Lesion
Choose the right efflorescences:
No scales are seen here.
Erosions are superficial defects; the patient could induce them by scratching, but has not done so here.
These are classic red-yellow grouped papules.
Diagnosis
Choose the right diagnosis:
The buttocks is a common spot for folliculitis, especially in those who sit a lot (desk jobs, truck drivers). One would expect pustules and more erythema, so the diagnosis is unlikely.
Very good. These are classic eruptive xanthomastiny red-yellow papules that appear suddenly, usually on buttocks. The patient almost certainly has elevated triglycerides and is at risk for diabetes mellitus. He must be evaluated by his family doctor or internist.
Allergic vasculitis usually features palpable purpura (not yellow papules) and is most common on the legs, not the buttocks.
Herpes occurs on the buttocks, but with group blisters, almost certainly unilateral, healing with erosions and crusts. In addition, herpes simplex is almost always symptomaticwith burning or itching.
Therapy
Choose the right therapy(ies):
A biopsy would be appropriate, but there are too many lesions to excise. In the case of xanthelasma with just a few lesions, excision is an option.
This is not an infection, so this approach has nothing to offer.
Of courseonce the diagnostic evaluation is complete. In rare instances, there are normolipemic xanthomas, so once cannot blindly start therapy.
Once again, lasers can destroy the lesions, but the real issue is defining the underlying abnormality. For xanthelasma, lasers are a good option to surgery.
Test
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