Differential Diagnosis for a Single Red Flaky Rash on the Forehead
Single Most Likely Diagnosis
- Seborrheic dermatitis: This condition is characterized by a well-defined, red, flaky rash, often found on the face, including the forehead. It's common in adults and can be triggered by stress, hormones, or environmental factors. The description and location of the rash, along with its duration, make seborrheic dermatitis a plausible diagnosis.
Other Likely Diagnoses
- Eczema (atopic dermatitis): Although more common in children, eczema can occur in adults and presents with red, itchy, and flaky skin. The forehead is a possible location, and the symptoms could match the description given.
- Contact dermatitis: This is a type of skin inflammation caused by contact with irritants or allergens. A well-defined rash could result from contact with a specific substance, and the forehead could be exposed to various products or materials that might cause a reaction.
- Psoriasis: While less common on the face, psoriasis can present with well-defined, red, scaly patches. The forehead is an uncommon but possible location, and the condition can appear at any age.
Do Not Miss Diagnoses
- Basal cell carcinoma: Although rare and less likely given the patient's age and the rash's appearance, basal cell carcinoma can sometimes present as a red, scaly patch. Given its potential to be deadly if missed and left untreated, it's crucial to consider this in the differential diagnosis.
- Lupus: Systemic lupus erythematosus (SLE) can cause a butterfly-shaped rash across the cheeks and nose but might also appear as a single lesion on the forehead. The condition has a wide range of symptoms, and a skin rash can be an early sign.
Rare Diagnoses
- Discoid lupus erythematosus: A chronic skin condition characterized by inflammation and scarring type of skin lesion, which can appear as a single red, scaly patch on the forehead.
- Sarcoidosis: A condition that can affect multiple parts of the body, including the skin, and might present with red, flaky rashes. It's less common and would typically be associated with other systemic symptoms.
- Cutaneous T-cell lymphoma (Mycosis fungoides): A rare type of skin cancer that can cause lesions that are red, scaly, and well-defined. It's an important consideration in the differential diagnosis due to its potential severity.