Differential Diagnosis for the Shoulder Rash
- Single most likely diagnosis
- Molluscum contagiosum: This diagnosis is the most likely due to the characteristic description of the rash, which includes pearly, flesh-colored, raised nodules with umbilicated centers. Molluscum contagiosum is a viral infection that presents with such lesions, often spread by skin-to-skin contact or through fomites.
- Other Likely diagnoses
- Keratosis pilaris: Although less likely, keratosis pilaris could be considered due to the presence of small, raised nodules. However, the umbilicated centers are not typical for keratosis pilaris, making molluscum contagiosum a more likely diagnosis.
- Warts: Caused by the human papillomavirus (HPV), warts can appear as raised, flesh-colored lesions. However, they typically do not have the characteristic umbilication seen in molluscum contagiosum.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Metastatic disease: Although extremely rare and unlikely, it's crucial not to miss a diagnosis of metastatic disease to the skin, which can present with nodular lesions. The context and additional symptoms would be critical in evaluating this possibility.
- Cutaneous lymphoma: Certain types of cutaneous lymphoma can present with skin nodules. Given the potential severity of lymphoma, it's essential to consider this in the differential diagnosis, especially if the lesions do not respond to initial treatment or if there are systemic symptoms.
- Rare diagnoses
- Syphilis (secondary): Syphilis can cause a wide range of skin manifestations, including nodular lesions. However, the description provided does not closely match the typical presentation of secondary syphilis, which often includes a maculopapular rash.
- Leishmaniasis: This parasitic infection can cause skin lesions, but they are typically ulcerative or crusted rather than the described pearly, umbilicated nodules.