Which factor most contributes to recurrent urinary tract infections (UTIs) in older men?

A. Hemolytic is incorrect because hemolytic anemia occurs when red blood cells are destroyed faster than they are produced, often due to autoimmune disorders, infections, certain medications, or inherited conditions. It is not primarily caused by dietary deficiency or blood loss.

B. Sickle-cell is incorrect because sickle-cell anemia is a genetic disorder in which abnormal hemoglobin causes red blood cells to take on a sickle shape, leading to hemolysis and impaired oxygen transport. Diet and blood loss do not cause this condition.

C. Pernicious is incorrect because pernicious anemia is caused by vitamin B12 deficiency, often due to the lack of intrinsic factor in the stomach, leading to impaired red blood cell production. While diet can contribute in rare cases, it is usually related to malabsorption, not simple dietary insufficiency.

D. Iron-deficiency is correct because this type of anemia results from insufficient iron, which is necessary for hemoglobin production. It is commonly caused by chronic blood loss (e.g., menstruation, gastrointestinal bleeding) or a diet low in iron. Without adequate iron, the body cannot produce enough hemoglobin, leading to small, pale red blood cells and symptoms like fatigue, pallor, shortness of breath, and dizziness. Iron supplementation and dietary changes are the main treatments.

A. Bacterial overgrowth of highly contagious S. aureus with development of vesicles and pruritus is incorrect because this description applies to impetigo, which is a superficial bacterial skin infection. Psoriasis is an autoimmune condition and is not contagious, so bacteria are not the primary cause.

B. Abnormal T-cell activation leading to excessive growth of keratinocytes and rapid epidermal shedding is correct because psoriasis is driven by dysregulation of the immune system. In this condition, T-cells become overactive and release cytokines that stimulate keratinocyte proliferation at an accelerated rate. Normally, keratinocytes take about 28–30 days to mature and shed, but in psoriasis, this process can occur in 3–5 days. The rapid turnover results in thickened, scaly plaques, redness, and inflammation. Chronic inflammation also contributes to the pruritus, discomfort, and erythema seen in affected areas. Triggers such as stress, infections, or certain medications may exacerbate the condition but do not cause it directly.

C. Sensitization on first exposure to an allergen with rash development on subsequent exposure is incorrect because this describes allergic contact dermatitis, where the immune system reacts to a previously encountered allergen. Psoriasis, in contrast, is autoimmune and does not require prior allergen exposure. The lesions are caused by internal immune dysregulation, not external sensitization.

D. Latent virus becomes reactivated by infection or stress, leading to development of skin lesions is incorrect because this mechanism describes viral conditions such as shingles (herpes zoster). Psoriasis is not caused by a virus, and the plaques and scales result from keratinocyte hyperproliferation due to immune dysregulation rather than viral reactivation.