Differential Diagnosis for Painful Pimples on Back
Single Most Likely Diagnosis
- Acne Vulgaris: This is the most common skin condition characterized by the occurrence of comedones (blackheads and whiteheads), pimples, and sometimes cysts or nodules. The back is a common area for acne due to the high concentration of sebaceous glands, which can become clogged and inflamed, leading to painful pimples.
Other Likely Diagnoses
- Folliculitis: An inflammatory condition affecting the hair follicles, often caused by bacterial or fungal infections. It presents as small, painful pimples or pus-filled bumps around the hair follicles on the back.
- Keratosis Pilaris: A condition characterized by the appearance of small, rough, sandpaper-like bumps on the skin, often on the back, due to the accumulation of keratin. While not typically painful, the bumps can be itchy and may become inflamed.
- Pityrosporum Folliculitis (Malassezia Folliculitis): A type of folliculitis caused by the yeast Malassezia, which is naturally found on the skin. It can cause itchy, painful pimples or bumps, particularly on the back and chest.
Do Not Miss Diagnoses
- Methicillin-Resistant Staphylococcus Aureus (MRSA) Infection: A serious bacterial infection that can cause painful pimples, boils, or abscesses. MRSA infections can spread quickly and are resistant to many antibiotics, making prompt diagnosis and treatment crucial.
- Squamous Cell Carcinoma or Other Skin Cancers: Although rare, any new or changing skin lesions, especially those that are painful or do not heal, should be evaluated for the possibility of skin cancer.
Rare Diagnoses
- Hidradenitis Suppurativa: A chronic skin condition characterized by recurring, painful abscesses or nodules in areas where skin folds occur, such as the back. It is less common than other conditions but can significantly impact quality of life.
- Erythema Nodosum: A condition that causes red, painful lumps to form, typically on the shins, but can occasionally appear on the back. It is often associated with an underlying infection, inflammatory condition, or medication reaction.
- Pilar Cysts (Trichilemmal Cysts): Benign cysts that originate from the hair follicles and can appear anywhere on the body, including the back. They are usually not painful unless they become inflamed or infected.