Riboflavin deficiency causes which of the following diseases ?

Riboflavin is vitamin B2, and its deficiency causes a cluster of signs called ariboflavinosis. The classic ones are cheilosis (cracks and fissures at the corners of the mouth), angular stomatitis, glossitis with a magenta tongue, and seborrhoeic dermatitis around the nose and eyes. So D is correct.

Why the others are wrong:

• Pellagra is due to niacin (B3) deficiency, with the classic triad of dermatitis, diarrhoea and dementia.
• Scurvy is due to vitamin C (ascorbic acid) deficiency, which impairs collagen formation and causes bleeding gums.
• Beri beri is due to thiamine (B1) deficiency, affecting nerves, heart and muscles.

Core concept: each B-complex vitamin has a characteristic deficiency picture, and cheilosis is the sign that points to riboflavin. For Mains, this links to micronutrient deficiency and nutrition under GS-II and GS-III food security and public health discussions.

Trap: candidates pick Pellagra because the name sounds like a B-vitamin disease, or they mix up B1, B2 and B3. Memorise the one-line signature of each vitamin.