Common types of acne include blackheads, whiteheads, papules, pustules and cysts. These types of acne are grouped into categories of inflammatory and non-inflammatory acne. Non-inflammatory acne, which is also known as comedonal acne, includes whiteheads and blackheads. Non-inflammatory acne is usually not painful and swollen like inflammatory acne.
Inflammatory acne results from the body's fight to contain an infection. The appearance of inflammatory acne is unlike basic acne bumps and appears red, deep, swollen and painful. Pustules and papules are typically filled with pus because they are inflamed. Nodules are large, firm bumps that form deep within the skin, while cysts are pus-filled lesions that resemble boils. Inflammatory acne, such as cysts and nodules, is considered a severe form of acne and should be checked by a dermatologist.