About.com states that while a mild case of red bumps after waxing is normal, dirt and oil on the skin can irritate the skin and cause red bumps. Waxing delicate skin or hard-to-remove hair can also cause red bumps, and the type of wax used along with skill of the waxing technician can also be a factor.
About.com suggests exfoliating the skin before waxing to remove the dead skin cells that contain dirt and oil; any contact with dirt or oil in the vulnerable state that skin is left in after waxing can irritate the skin and cause red bumps. Exfoliation also raises the hair on the skin for easier removal and a lessened risk of irritation, and applying heat to the body before waxing opens pores for similar results.
About.com states that different waxes work best in certain areas; using hard wax in the bikini area and cream wax on delicate facial skin may reduce the occurrence of red bumps. The skill of a waxing technician is also a determining factor for the appearance of red bumps; he may not have the experience or possess the best products for waxing certain skin and hair types. Application of hydrocortizone cream can prevent red bumps if improper tactics or products are used.