Differential Diagnosis for Rash in Axilla and Down Right Side of Abdomen
Single Most Likely Diagnosis
- Contact Dermatitis: This is a common condition that occurs when the skin comes into contact with an irritant or allergen, leading to a rash. The axilla and abdominal area are prone to friction and exposure to various substances, making contact dermatitis a plausible explanation for the rash in these areas.
Other Likely Diagnoses
- Intertrigo: A type of skin inflammation caused by friction and moisture, often seen in skin folds like the axilla. It can spread down the abdomen if the conditions persist.
- Eczema (Atopic Dermatitis): A chronic skin condition characterized by itchy, inflamed skin. It can appear anywhere on the body, including the axilla and abdomen, especially if there's a personal or family history of atopic diseases.
- Psoriasis: An autoimmune condition that speeds up the life cycle of skin cells, causing cells to build up rapidly on the surface of the skin. The lesions can appear anywhere, including the axilla and down the sides of the abdomen.
Do Not Miss Diagnoses
- Shingles (Herpes Zoster): Although less common, shingles can present as a rash in a dermatomal distribution, which could include the axilla and down one side of the abdomen. Missing this diagnosis could lead to delayed antiviral treatment and potential complications like postherpetic neuralgia.
- Lymphoma Cutis: A rare manifestation of lymphoma that presents as skin lesions. While extremely uncommon, it's crucial not to miss this diagnosis due to its severe implications.
Rare Diagnoses
- Pityriasis Rosea: A skin condition characterized by a rash that typically starts with a single, large spot called a herald patch, followed by an eruption of smaller spots. It can appear on the abdomen but is less commonly confined to one side.
- Granuloma Annulare: A benign skin condition characterized by small, circular bumps that are often localized to one area of the body. It's rare but could potentially present in the described pattern.
- Erythema Marginatum: A rash associated with acute rheumatic fever, which, although rare, could present with a rash on the trunk and could be considered in the differential diagnosis, especially if there are other systemic symptoms.