**Core Concept**
Topical steroids are potent anti-inflammatory agents used to treat various skin conditions. However, long-term use can lead to several complications due to their systemic absorption and suppression of the hypothalamic-pituitary-adrenal (HPA) axis.

**Why the Correct Answer is Right**
Topical steroids can cause atrophy of the skin, especially in areas with thin skin such as the face, neck, and genitalia. This is due to the suppression of cortisol production by the adrenal glands, leading to a decrease in the production of cortisol and its precursors. Additionally, topical steroids can cause telangiectasia, striae, and hypopigmentation, which are all signs of skin atrophy.

**Why Each Wrong Option is Incorrect**
**Option A:** Local infections are not a direct complication of topical steroids. However, the suppression of the immune system by long-term use of topical steroids can increase the risk of infections.

**Option B:** Allergic contact dermatitis is an adverse reaction to a particular ingredient in the topical steroid formulation, not a direct complication of its use.

**Option C:** While topical steroids can cause some systemic effects, they are not typically associated with the development of hypertension.

**Clinical Pearl / High-Yield Fact**
It's essential to use the lowest effective concentration and potency of topical steroid for the shortest duration necessary to avoid complications. This is especially true for children, pregnant women, and individuals with a history of skin atrophy.

**Correct Answer: D. Skin atrophy.**