Differential Diagnosis for Red, Raised, Dry Papule

Single Most Likely Diagnosis

• Eczema/Dermatitis: This is a common condition that can present with red, raised, and dry papules due to inflammation of the skin. The size of approximately 0.5–0.6 cm fits within the range of what might be expected for a localized area of dermatitis.

Other Likely Diagnoses

• Psoriasis: A chronic skin condition characterized by thick, red, and scaly patches. While psoriasis often presents with larger plaques, smaller papules can occur, especially in the early stages or in certain variants like guttate psoriasis.
• Keratosis Pilaris: A condition that causes small, rough, sandpaper-like bumps on the skin, often on the arms, legs, or buttocks. These can sometimes appear red and dry, especially if irritated or inflamed.
• Insect Bite Reaction: Reactions to insect bites can cause red, raised, and sometimes dry papules, depending on the individual's immune response and the type of insect.

Do Not Miss Diagnoses

• Basal Cell Carcinoma: Although less common and typically presenting differently, basal cell carcinoma can sometimes appear as a small, red, raised lesion. Given its potential for malignancy, it's crucial not to miss this diagnosis.
• Squamous Cell Carcinoma: Similar to basal cell carcinoma, squamous cell carcinoma is a type of skin cancer that can present with red, raised lesions, although they often have a more irregular appearance and may ulcerate.
• Lupus: Systemic lupus erythematosus (SLE) can cause skin lesions, including red, raised papules. The presence of other systemic symptoms would help differentiate this from more common skin conditions.

Rare Diagnoses

• Granuloma Faciale: A rare skin condition characterized by single or multiple, reddish-brown, soft to firm, painless nodules or plaques, typically on the face. It could potentially present as a solitary red, raised papule.
• Sarcoidosis: A condition that can affect multiple parts of the body, including the skin, where it may cause red, raised papules among other types of lesions. Sarcoidosis is relatively rare and would typically be accompanied by other systemic symptoms.
• Cutaneous Lymphoma: Certain types of cutaneous lymphoma, like mycosis fungoides, can present with a variety of skin lesions, including papules. However, these conditions are rare and usually have a more complex presentation.