Differential Diagnosis for a 5-year-old with a Generalized Rash
Single most likely diagnosis
- Insect bites or allergic contact dermatitis: This is the most likely diagnosis given the patient's recent outdoor activity in the woods at daycare, which increases the risk of exposure to insects, plants, or other allergens that could cause a rash.
Other Likely diagnoses
- Eczema (atopic dermatitis): The itchy, small red bumps could be indicative of an eczema flare-up, especially if the child has a history of atopic diseases.
- Impetigo: A highly contagious bacterial skin infection that can cause red, itchy bumps and is common in children, especially in daycare settings.
- Viral exanthem: Various viral infections can cause rashes in children, and the fact that the rash started at daycare suggests possible exposure to a viral pathogen.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Meningococcemia: Although rare, this condition can present with a rash and is life-threatening if not promptly treated. The rash associated with meningococcemia is typically petechial or purpuric.
- Stevens-Johnson Syndrome (SJS) or Toxic Epidermal Necrolysis (TEN): These are severe skin and mucous membrane disorders, usually a reaction to medication or infection, which can be fatal if not recognized and treated early.
Rare diagnoses
- Lyme disease: Given the patient's exposure to the woods, Lyme disease is a possibility, although it typically presents with a distinctive "bull's-eye" rash (erythema migrans) rather than generalized small red bumps.
- Rocky Mountain spotted fever: Another tick-borne illness that can cause a rash, although it is less common and typically presents with a characteristic spotted rash.