The correct answer is seborrhea (choice “c”), aka seborrheic dermatitis, a papulosquamous condition known to affect a variety of areas, including the groin and axillae. This patient could have had a close cousin of seborrhea, psoriasis (choice “a”), but he was missing corroborative involvement of his elbows, knees, and nails.
Groin rashes are often misdiagnosed as “yeast infections” (choice “b”); however, candidal involvement of the groin is actually quite unusual in men, and it would almost certainly have responded well to the imidazoles the patient had tried.
Eczema (choice “d”) is certainly common enough, but it is almost invariably highly pruritic and seldom affects the groin exclusively. It is therefore an unlikely choice.
This case nicely illustrates several useful points. One is that the differential for groin rashes is extensive (18 items long!) and demands careful thought, since cancer (eg, cutaneous T-cell lymphoma and extramammary Paget’s disease) can present as a rashlike eruption in the groin. The lack of response to the “usual and customary” treatments is precisely what should prompt further consideration.
Another learning point to be gleaned from this case is: When stumped, look elsewhere. Can’t figure out the groin rash? Look elsewhere, anywhere, for clues, when puzzled. In this case, finding signs of seborrhea elsewhere raised that possibility in the groin as well. Corroboration was also provided by the history of antecedent stress, a well-known trigger for flares of seborrhea, and by the relative lack of symptoms.
Treatment in this case entailed hydrocortisone 2.5% cream, but the real “cure” will only come with serious reduction of the patient’s stress level. His topical steroid use will be limited to no more than five consecutive days, with a break for two consecutive days per week.
Our real contribution to this patient’s well-being is in establishing the correct diagnosis and “selling” it to the patient, optimizing his confidence in the benignancy and self-limiting nature of his problem.