Hello, Thanks for writing to us. Contact dermatitis can develop if the waist area comes into direct contact with an irritating substance such as dye in clothing, detergents, latex, soaps or poison ivy. Seborrheic dermatitis, caused by extreme temperatures, infrequent bathing or lotions that contain alcohol, can also cause pimple-like bumps. They can also be the result of conditions such as eczema, psoriasis, impetigo or shingles. skin can often be treated with the application of calamine lotion, anti-dandruff shampoo, oatmeal bath products, thick moisturizing lotions or 1 percent hydrocortisone cream. Also, a doctor can prescribe an oral antibiotic or anti-fungal cream to treat bacteria-related rashes such as impetigo. If you suffer from a skin condition like psoriasis, ultraviolet light therapy can be beneficial as well. I do hope that you have found something helpful and I will be glad to answer any further query.