Differential Diagnosis for Lumps on the Head that are Painful to the Touch

Single Most Likely Diagnosis

• Furuncle or Carbuncle: These are skin infections of the hair follicles that can cause painful lumps on the head. They are common and can be caused by bacterial infections, typically Staphylococcus aureus.

Other Likely Diagnoses

• Cyst: Sebaceous cysts or epidermoid cysts can form on the scalp and may become inflamed, causing pain. They are benign but can become infected.
• Abscess: Similar to furuncles, abscesses are collections of pus that can form on the scalp, often due to bacterial infection, and are painful.
• Ingrown Hair (Folliculitis): This condition occurs when hair grows back into the skin, causing inflammation, which can lead to painful lumps.
• Seborrheic Keratosis: While typically not painful, if irritated or inflamed, these benign growths can cause discomfort and may be mistaken for painful lumps.

Do Not Miss Diagnoses

• Meningioma: Although rare, a meningioma (a type of brain tumor) can cause a lump on the skull if it grows large enough to erode through the bone. It's crucial to distinguish this from other causes due to its serious implications.
• Osteoma: A benign bone tumor that can cause a lump on the skull. While not typically painful, if it presses on nerves or grows in a sensitive area, it could cause discomfort.
• Metastatic Disease: In rare cases, cancer that has spread from another part of the body can cause lumps on the scalp or skull. This would be a critical diagnosis not to miss due to its severe implications.

Rare Diagnoses

• Dermatofibroma: A benign skin growth that can appear as a firm lump, usually after a minor injury, and can be found on the scalp.
• Lipoma: A benign tumor made up of fat tissue that can rarely occur on the scalp and cause a lump.
• Neurofibroma: Part of neurofibromatosis type 1, these are benign nerve sheath tumors that can cause lumps on the scalp, among other places.

Each of these diagnoses has a different approach to treatment, ranging from watchful waiting for benign conditions to urgent medical or surgical intervention for more serious conditions. A thorough medical evaluation, including history, physical examination, and possibly imaging or biopsy, is necessary to determine the cause of the lumps and appropriate treatment.