Differential Diagnosis
- Single most likely diagnosis:
- Melasma and hypertrichosis due to pregnancy: The patient's symptoms of progressive darkening of the face, particularly over the nasal bridge and cheeks, and increased hair on the upper lip are consistent with melasma and hypertrichosis, which are common in pregnancy due to hormonal changes.
- Other Likely diagnoses:
- Striae distensae (stretch marks) with associated pruritus: The patient's itching over the stretch marks on the abdomen and chest is a common complaint in pregnancy.
- Spider angiomas due to pregnancy: The presence of multiple blanching, 1- to 2-cm spider angiomas on the chest is also consistent with pregnancy-related changes.
- Benign nevi or freckles: The patient's multiple freckles on bilateral extremities and the black-tan nevus with irregular borders on the lower extremity are likely benign and unrelated to her pregnancy.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Cholestasis of pregnancy: The patient's pruritus could also be a symptom of cholestasis of pregnancy, a condition that can have serious consequences for the fetus if left untreated.
- Malignant melanoma: Although the patient's nevus has irregular borders, which is a concerning feature for melanoma, the overall clinical presentation is more consistent with a benign nevus. However, it is essential to monitor the lesion for any changes.
- Rare diagnoses:
- Addison's disease: The patient's hyperpigmentation could be a symptom of Addison's disease, although this is unlikely given the absence of other symptoms such as hypotension, weight loss, or electrolyte imbalances.
- Porphyria cutanea tarda: This rare genetic disorder can cause blistering skin lesions, hypertrichosis, and hyperpigmentation, but it is unlikely given the patient's lack of other symptoms such as blistering lesions or sensitivity to sunlight.