This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Scabies and other infestations, Subject name: Dental
Disorder of hyperkeratinization? 
Select and explain. 
A. Icthyosis vulgaris, B. Vitiligo, C. Atopic dermatitis, D. Seborrhic dermatitis
A: Icthyosis vulgaris
Answer: A: Icthyosis vulgaris 
Explanation: Hyperkeratinization: Icthyosis vulgaris Vitiligo is hypopigmentry disorder. Atopic dermatitis: itchy lichenified lesions over flexors of elbow and knee Seborrheic dermatitis: scaly lesion Icthyosis vulgaris: AD disorder Reduced or absence of filaggrin protein and granular layer Fish-like scales on the skin.