Allergy and topical irritation associated with transdermal testosterone administration: a comparison of scrotal and nonscrotal transdermal systems.

BACKGROUND

Topical effects are the most common adverse event for the scrotal and nonscrotal transdermal testosterone systems.

OBJECTIVE

The study compared topical irritation rates for scrotal (Testoderm Testosterone Transdermal System; ALZA Corporation, Palo Alto, CA) and nonscrotal (Androderm Testosterone Transdermal System; SmithKline Beecham Pharmaceuticals, Philadelphia, PA) products.

METHODS

This open-label, crossover study randomized 60 healthy, adult males to 14 days each of two treatments: one 40-cm2 scrotal system delivering approximately 4 mg testosterone over 24 hours, or two 37-cm2 nonscrotal systems worn on the back or upper outer arm, providing approximately 5 mg testosterone over 24 hours. Severity of topical effects was scored at system removal.

RESULTS

Allergic contact dermatitis and spontaneous flaring of prior application sites occurred in 7 (12%) subjects using nonscrotal systems on Day 12; no confirmed cases of allergy to the scrotal system were observed (p < 0.001). For scrotal and nonscrotal systems respectively, moderately intense irritation was noted immediately after system removal in 5% and 32% of subjects (p < 0.001), and in 1% and 7% of systems applied (p < 0.001).

CONCLUSION

Scrotal systems produced no confirmed contact allergy and less topical irritation than nonscrotal systems. The four subjects with contact allergy to nonscrotal systems used the scrotal system without a reaction, suggesting testosterone was not the allergen.