A 30-year-old with a facial rash and normal secondary sexual characteristics is suspected to have which condition?

The presence of a facial rash in conjunction with normal secondary sexual characteristics points towards a dermatological condition rather than a hormonal or reproductive issue. Seborrhoeic dermatitis is a chronic inflammatory skin condition that often causes scaly patches, red skin, and dandruff. It can appear on various areas of the body, including the face, leading to the characteristic rash described in the scenario.

In this case, the individual is a 30-year-old, and if they are exhibiting normal secondary sexual characteristics, it suggests that their hormonal and reproductive systems are functioning properly. This helps rule out conditions such as hypothalamic amenorrhea and post-contraceptive pill amenorrhea, both of which would typically involve some dysregulation in hormonal balance, potentially leading to abnormal menstrual cycles or secondary sexual development.

Polycystic ovary syndrome (PCOS) could sometimes present with skin issues like acne or hirsutism due to excess androgen production, but it would generally also be associated with menstrual irregularities or other metabolic signs, such as obesity or insulin resistance, which are not indicated here. Therefore, the clinical vignette strongly aligns with seborrhoeic dermatitis as the most likely diagnosis when considering the symptoms presented.