Differential Diagnosis for Hand and Foot Rash
Single Most Likely Diagnosis
- Contact Dermatitis: The patient's symptoms of hand and foot rash, postnasal drip, and recent use of OTC allergy medications suggest an allergic reaction, which is consistent with contact dermatitis. The acute onset and association with postnasal drip also support this diagnosis.
Other Likely Diagnoses
- Atopic Dermatitis (Eczema): The patient's symptoms of rash and postnasal drip could be indicative of atopic dermatitis, especially if the patient has a history of allergies or asthma.
- Irritant Contact Dermatitis: Similar to contact dermatitis, irritant contact dermatitis could be a possible diagnosis, especially if the patient has been exposed to harsh chemicals or soaps.
- Allergic Contact Dermatitis: This diagnosis is also possible, especially if the patient has been exposed to a new substance that triggered an allergic reaction.
Do Not Miss Diagnoses
- Stevens-Johnson Syndrome: Although unlikely, Stevens-Johnson syndrome is a life-threatening condition that requires prompt recognition and treatment. The patient's symptoms of rash and postnasal drip could be indicative of this condition, especially if the patient has recently started a new medication.
- Toxic Epidermal Necrolysis: Similar to Stevens-Johnson syndrome, toxic epidermal necrolysis is a life-threatening condition that requires prompt recognition and treatment.
- Infectious Etiologies (e.g., Impetigo, Cellulitis): Although the patient does not have symptoms of fever or dyspnea, infectious etiologies should still be considered, especially if the patient has a history of exposure to infectious agents.
Rare Diagnoses
- Kawasaki Disease: This rare condition is characterized by a rash, fever, and lymphadenopathy, but the patient's lack of fever and lymphadenopathy makes this diagnosis less likely.
- Pityriasis Rubra Pilaris: This rare skin condition is characterized by a rash and palmoplantar keratoderma, but the patient's symptoms do not fully align with this diagnosis.
- Erythema Multiforme: This rare condition is characterized by a rash and target lesions, but the patient's symptoms do not fully align with this diagnosis.