Red, dot-like rashes on the elbows and behind the knees that are spreading are often seen in conditions like eczema (atopic dermatitis) or certain types of dermatitis, rather than just a simple sand allergy, especially when they persist without exposure. Treatment usually involves keeping the skin well moisturised with a gentle, fragrance-free cream, avoiding harsh soaps and irritants, and using prescribed anti-inflammatory creams (if advised by a doctor) to reduce redness and itching, while also wearing soft cotton clothing and keeping the skin cool and dry. Since the rash is spreading, it is important to consult a dermatologist for an accurate diagnosis and the right treatment plan, as early and proper management can prevent worsening and provide relief.