Differential Diagnosis for Fine Sandpaper Rash on Arms in a 22yo Female

Single Most Likely Diagnosis

• Keratosis Pilaris: A common skin condition characterized by small, rough, sandpaper-like bumps on the skin, often on the arms, due to keratin buildup. It's benign and matches the description provided.

Other Likely Diagnoses

• Eczema (Atopic Dermatitis): Can present with a sandpaper-like rash, especially if the skin is dry and irritated. It's a common condition that can cause skin dryness and inflammation.
• Dry Skin (Xerosis): Especially in cold or dry environments, can lead to a sandpaper-like texture on the skin due to dehydration of the skin cells.
• Folliculitis: An inflammation of the hair follicles, which can cause a rash that might feel like sandpaper, especially if it's due to friction or shaving.

Do Not Miss Diagnoses

• Scarlet Fever: Although less common, it's crucial not to miss this diagnosis. Scarlet fever is characterized by a sandpaper-like rash that appears after a sore throat, caused by Group A beta-hemolytic streptococci. It requires antibiotic treatment.
• Toxic Shock Syndrome: A rare but life-threatening condition that can start with a rash, among other symptoms like fever and vomiting. It's associated with bacterial infections and requires immediate medical attention.

Rare Diagnoses

• Pityriasis Rubra Pilaris (PRP): A rare skin disorder that causes constant inflammation and scaling (exfoliation) of the skin. It can present with a sandpaper-like rash but is much less common than other conditions listed here.
• Ichthyosis: A group of skin conditions that cause dry, scaly, and thickened skin, which might feel like sandpaper. It's relatively rare and often inherited.