​Differential diagnosis of long QT syndrome 
-hypothermia 
-stroke 
-subarachnoid hemorrhage 
-significant bradycardia
-myocardial ischemia 
-left ventricular hypertrophy 
-second degree AV block 
-third degree AV block 
-congenital long QT syndrome 
-prednisone 
-antibiotics such as  erythromycin, trimethoprim-sulfamethoxazole, levofloxacin, ketoconazole, itraconazole
-astemizole, terfenadine 
-tricyclic antidepressants
-class 1a anti arrhythmic ( quinidine, procainamide) 
-class 1c anti arrhythmic ( propafenone) 
-class III anti arrhythmic ( amiodarone, sotalol, bretylium) 
hypocalcemia 
-hypomagnesemia 
-hypokalemia 

​Differential diagnosis of loiasis / loa loa infections 
-cysticercosis 
-bacterial pyoderma 
-onchocerciasis / river blindness
-filariasis 
-myiasis 
-gnathostomiasis 
-cutaneous larva migrans 
-dracunculiasis 

​Differential diagnosis of liver mass 
-focal nodular hyperplasia 
-amebic abscess
-pyogenic abscess
-congenital cyst 
-echinococcal . hydatid cyst 
-association with polycystic kidney disease
-liver cell adenoma 
-hemangioma 
-metastatic cancer 
-hepatocellular carcinoma 

​Differential diagnosis of livedo reticularis 
-thromboangiitis obliterans / Buerger’s disease
-rheumatoid arthritis 
-dermatomyositis 
-systemic lupus erythematosus 
-antiphopholipid antibody syndrome 
-cholesterol emboli 
-polyarteritis nodosa 
-occult malignancy 
-benign idiopathic 

​Differential diagnosis of lichen simplex chronicus 
-tinea corporis 
-discoid eczema 
-nummular dermatitis 
-atopic dermatitis
-eczema 
-lichen planus 
-psoriasis 

​Differential diagnosis of lichen planus 
-leukoplakia 
-lichen sclerosus 
-bullous pemphigoid 
-pemphigus vulgaris 
-erythema multiforme
-candidiasis 
-discoid lupus erythematosus 
-pityriasis rosea 
-secondary syphilis 
-lichen simplex chronicus 
-psoriasis 
-drug eruption 

​Differential diagnosis of oral  leukoplakia
-pseudoepitheliomatous hyperplasia 
-necrotizing sialometaplasia 
-secondary syphilis 
-white sponge nevus 
-oral hairy leukoplakia 
-oral candidiasis 
-lichen planus 
-dysplasia or carcinoma 
-cheek biting 
-tobacco 
-dentures 

​Differential diagnosis of leptospirosis 
-relapsing fever 
-hemorrhagic fever such as Hantavirus 
-dengue 
-yellow fever 
-viral hepatitis 
-influenza
-bacterial meningitis 

​Differential diagnosis of mucocutaneous leishmaniasis 
-yaws
-polymorphic reticulosis 
-sarcoidosis 
-lymphoma 
-syphilis 
-Wegener’s granulomatosis 
-paracoccidioidomycosis 
-nasopharyngeal carcinoma 

​Differential diagnosis of cutaneous leishmaniasis 
-yaws
-fungal infection 
-Hansen’s disease
-cutaneous tuberculosis 
-syphilis 
-sarcoidosis 
-neoplasm