Differential Diagnosis for Raised Red Bumps on Abdominal Trunk
Single Most Likely Diagnosis
- Contact Dermatitis: This is the most likely diagnosis given the history of yard work, which increases the risk of exposure to allergens or irritants such as plants (e.g., poison ivy, oak, or sumac), pesticides, or other chemicals. The symptoms of raised red nickel-sized bumps that are pruritic (itchy) are consistent with an allergic contact dermatitis reaction.
Other Likely Diagnoses
- Insect Bites: Yard work can also expose individuals to various insects, and bites from these insects can cause raised, red, and itchy bumps. Common culprits include mosquitoes, chiggers, and fleas.
- Folliculitis: This condition involves inflammation of the hair follicles and can be caused by friction, sweat, or bacterial infection. It presents as small, red, and sometimes itchy bumps, which could fit the description provided.
- Heat Rash (Miliaria): Engaging in physical activity like yard work, especially in warm weather, can lead to heat rash. This condition is characterized by small, raised red bumps due to blocked sweat ducts and can be itchy.
Do Not Miss Diagnoses
- Allergic Reaction to a Medication: Although less likely, an allergic reaction to a medication (if the patient has recently started a new drug) could present with similar symptoms. This is crucial to consider because some allergic reactions can be severe and even life-threatening (e.g., anaphylaxis).
- Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN): These are severe skin conditions usually triggered by medications. They can start with what seems like a minor skin reaction but can rapidly progress to widespread skin necrosis and detachment, which is life-threatening.
Rare Diagnoses
- Erythema Multiforme: A skin condition characterized by target lesions, which are raised, red, and sometimes itchy. It can be triggered by infections or medications and, although rare, should be considered in the differential diagnosis due to its distinctive appearance and potential severity.
- Pityriasis Rosea: An inflammatory skin condition that starts with a single large spot (herald patch) followed by an eruption of smaller spots, typically on the trunk. The spots can be itchy and might fit the description given, although the pattern and progression are usually more characteristic.