Hand, Foot, and Mouth Disease (HFMD): This is the most common diagnosis for a rash on the hands and feet in pediatric patients, typically caused by Coxsackievirus A or Enterovirus 71. It's characterized by vesicular lesions on the palms, soles, and sometimes the buttocks, along with fever and oral ulcers.

Kawasaki Disease: An acute febrile illness that predominantly affects children, characterized by fever, rash, swelling of hands and feet, conjunctivitis, and cervical lymphadenopathy. The rash can vary but often includes the hands and feet.
Impetigo: A highly contagious bacterial skin infection that can cause red sores on the hands and feet, though it's less specific to these areas compared to HFMD.
Eczema (Atopic Dermatitis): While not typically causing a rash limited to the hands and feet, eczema can affect these areas and is common in pediatric patients.

Meningococcemia: A severe infection caused by Neisseria meningitidis, which can present with a rash (often petechial or purpuric) that can appear anywhere on the body, including the hands and feet. It's critical to identify this condition early due to its high mortality rate if untreated.
Rocky Mountain Spotted Fever (RMSF): A tick-borne illness caused by Rickettsia rickettsii, characterized by fever, headache, and a rash that typically starts on the wrists and ankles before spreading to other areas.
Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis: Severe skin and mucous membrane disorders, usually a reaction to medication or infection, which can present with a rash and skin detachment, including on the hands and feet.

Palmoplantar Pustulosis: A rare skin condition characterized by pustules on the palms of the hands and soles of the feet, often associated with psoriasis.
Keratoderma Blennorrhagicum: Associated with Reiter's syndrome, it causes skin lesions on the palms and soles.
Secondary Syphilis: Can cause a rash on the palms and soles, among other symptoms, though this is less common in pediatric patients unless congenitally acquired.