ANSWER
The correct answer is to perform a biopsy (choice “d”). Although the other choices can be part of the workup for scalp conditions (eg, secondary syphilis, lupus, or fungal infection), the most logical step is to assess the basic histopathologic process. This would provide the clearest direction by revealing characteristic changes in the tissues. Starting an oral antibiotic, such as minocycline, might be a reasonable step if biopsy were not possible.
DISCUSSION
This is a typical case of “scarring alopecia,” a category of hair loss with a wide-ranging differential diagnosis. Included in it would be lymphoma-associated perifollicular mucinosis, discoid lupus, lichen planopilaris (lichen planus affecting the scalp), tinea capitis, secondary syphilis, and pseudopelade. All potentially lead to permanent hair loss; therefore, direct and timely diagnostic information that only a biopsy can provide is essential.
Fungal origin was unlikely for several reasons. Such a diagnosis would be distinctly unusual in a Caucasian woman of this age, particularly since no source (child, spouse, or pet) was identified. The lack of epidermal changes (scale or other broken skin), edema, or adenopathy was a key factor in that regard as well.
In this and most such cases, a 4-mm punch biopsy is taken from the (presumably) active margin of the radially expanding pathologic process; biopsy of the centers would likely only show scar. The biopsy should include at least a few hair shafts, with care taken to penetrate the skin at the same angle from which the hairs emerge. This facilitates collection of the length of the shaft, which could provide valuable diagnostic information.
Done under local anesthesia with lidocaine/epinephrine, the defect is almost always closed with surface sutures, for hemostasis and to speed healing. If one felt strongly about the possibility of infection, an additional sample could be taken and submitted for bacterial and fungal cultures; in this case, neither was suspected.
The results in this case proved the diagnosis of pseudopelade, an inflammatory condition of unknown origin, possibly representing the end-point of either discoid lupus or lichen planopilaris. In any case, the other potential causes of scarring alopecia were ruled out, and appropriate treatment (perilesional injection of 5 mg per cc triamcinolone suspension, oral minocycline 100 mg bid, and topical betamethasone foam) were instituted and follow-up arranged.