Simple cases
Case 24
48-year-old truck driver was evaluated for persistent rosacea. At the end of the consultation, the patient asked about a rash in his groin.
History
Do you have diabetes?
No.
Diabetes mellitus may predispose to cutaneous infection. Always search for potential causes.
Do you sweat a lot?
Yes, especially in summer when I spend all day driving. I have a special seat cover but it doesn't help much.
Sweating is another possible predisposing factor for all groin rashes.
How long have you had these lesions?
A long timethey come and gothis time at least a month.
The clinical course often gives clues to the etiology.
Has this problem been treated?
No.
Previous therapy can alter the clinical picture. In this area, irritant or allergic contact dermatitis is a possibility.
How much do you weigh?
Around 90 to 95 kilograms.
Always look for possible causes. Obesity is another predisposing factor.
Do you smoke?
I smoke a pipe once in a while?
Not a helpful question? Why did you ask this?
Lesion
Choose the right efflorescences:
The lesion is flat and probably best described as an erythema.
The skin is not thinned or depressed.
You can see something, even if it is subtle.
No scales are seen.
Diagnosis
Choose the right diagnosis:
No history of diaper use.
Erythrasma is caused by Corynebacteria minutissimum. The lesions show coral red fluorescence when examined with a Wood light.
Tinea inguinalis without scale is unlikely, unless it had been treated.
Contact dermatitis should have vesicles, papules, or later scale and lichenification. Dermatitis is usually not so well circumscribed.
While the location is perfect, hidradenitis suppurativa consists of boils or abscesses.
Therapy
Choose the right therapy(ies):
Low-dose systemic erythromycin is a suitable treatment. Recurrences are common.
The easiest and cheapest way to treat. The imidazoles, although developed as antifungals, also effectively treat erythrasma.
Corticosteroids are not indicated for bacterial infections. In addition, high potency corticosteroids should never be used in the groin.
Designed for psoriasis and far too irritating for the groin.
