Differential Diagnosis for a 15-year-old Male with a Pimple-like Lesion on the Buttocks
- Single most likely diagnosis:
- Furuncle or Carbuncle: The patient's history of a pimple-like lesion that developed into a larger, painful, and purulent lesion is consistent with a furuncle (boil) or carbuncle. The fact that it drained a large amount of purulent material and then partially resolved, only to start oozing again, supports this diagnosis. The tan/grayish color of the oozing material could be indicative of the presence of bacteria, such as Staphylococcus aureus, which is commonly found in furuncles and carbuncles.
- Other Likely diagnoses:
- Abscess: An abscess is a collection of pus that has built up within the tissue of the body. The patient's symptoms of a painful lesion with purulent drainage are consistent with an abscess. The fact that the lesion partially resolved after draining and then started oozing again could indicate that the abscess is not fully resolved.
- Cyst or Epidermoid Cyst: The patient's lesion could be a cyst or epidermoid cyst that has become infected, leading to the purulent drainage. The fact that the lesion is located on the buttocks and has a history of oozing a tan/grayish material supports this diagnosis.
- Hidradenitis Suppurativa: This is a chronic skin condition that involves the apocrine glands, leading to recurrent, painful abscesses and nodules. The patient's symptoms of a painful lesion with purulent drainage, particularly in the buttocks area, could be consistent with hidradenitis suppurativa.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Necrotizing Fasciitis: Although rare, necrotizing fasciitis is a life-threatening condition that requires prompt diagnosis and treatment. The patient's symptoms of a painful lesion with purulent drainage could be indicative of necrotizing fasciitis, particularly if there are signs of systemic illness, such as fever or tachycardia.
- Osteomyelitis: Osteomyelitis is an infection of the bone that can occur as a result of a skin infection. The patient's symptoms of a painful lesion with purulent drainage could be indicative of osteomyelitis, particularly if there is a history of trauma or if the patient has a fever.
- Rare diagnoses:
- Pilonidal Cyst or Sinus: A pilonidal cyst or sinus is a rare condition that involves a cyst or tunnel in the skin, typically located near the tailbone. The patient's symptoms of a painful lesion with purulent drainage could be consistent with a pilonidal cyst or sinus.
- Actinomycosis: Actinomycosis is a rare bacterial infection that can cause abscesses or lesions on the skin. The patient's symptoms of a painful lesion with purulent drainage could be indicative of actinomycosis, particularly if there is a history of trauma or if the patient has a fever.