This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral Cavity, Subject name: ENT
Presence of Wickham's striae in the oral cavity is a manifestation of: 
Select and explain. 
A. HIV infection, B. Lichen planus, C. Leukemia, D. Oral candidiasis
B: Lichen planus
Answer: B: Lichen planus 
Explanation: Wickham's striae are interlacing white lines in the buccal mucosa seen in lichen planus - a skin disorder.HIV infection presents with oral Candida infection, angular cheilitis, hairy leukoplakia, periodontitis, gingivitis, diffuse parotid enlargement, recurrent herpetic infections of the oral cavity causing ulcers and Kaposi's sarcoma.Leukaemia presents with gum hypertrophy, petechiae of mucous membrane of oral cavity, pale oral mucosa and oral ulcers.Oral candidiasis presents in three forms:(i). As a thrush, white patches are formed in oral mucosa or tongue and when wiped leave a red base.(ii). Chronic hypertrophic form presents as a white patch that cannot be wiped off.(iii). Atrophic form presents as red ulcerated mucosa without any pseudomembrane. It is seen in those using long-term antibiotics, steroids or cytotoxic drugs.