Small pox

This is a very ancient and one of the most dreadful diseases i have ever heard about. It is a viral disease in which at first, prominent fluid filled blisters, very similar to pimples are formed on whole body. These blisters are very leaky and make one's life hell. If you are lucky enough to pass through this misery then these pimples are dried and they leave permanent spots on your body making life more painful. This odd disease was also known as "Red plague" and it has caused the death of millions of people up to 1979. At this moment, this is the only known disease that has been completely eradicated from world. Most known cases of this painful disease include "Abraham Lincoln". 
              

             

Cholera

Cholera is a very weird bacterial disease which causes infection of small intestine. As a result, severe diarrhea and vomiting occurs  leading to death in a few hours if untreated. Person becomes extremely dehydrated resulting in severe thirst, low blood pressure, wrinkled skin, muscle cramps and "Rice water" stools. Treatment of this disease is hydration of patient with intravenous transmission of salts as much as possible. This dangerous disease is also known as "Blue death" because of blue grayish appearance of patient's skin in severe cases.

              

                

Alien hand syndrome

Imagine yourself relaxing on a chair on a pleasant Sunday morning, when suddenly one of your hand rises and tries to kill you by tightly gripping your throat , trying to strangle you. You will lose your fingers with other hand and escape from this unwilling suicide. Although, it seems like a screen shot of 19th century average horror movie but if you are patient of this weird syndrome then all of this can happen to you. Main cause of this abnormal neurological disease is dissociation between two parts of brain due to injury of their junction i.e "Corpus callosum ". As a result, involuntary movements of limbs starts without knowing. Recently, no treatment has been found, it can be controlled only by trying to keep hands busy by handling different objects.

                 

Progeria

Progeria is a very rare genetic disease which is characterized by "Early aging". Patient looks like an old child with bald head due to hair loss, wrinkled skin, joint problems and mainly heart diseases and stroke. Their body is very fragile like old people. These patients have broad head with prominent scalp veins, narrow face and prominent eyes. Recently, only 53 cases of this disease have been diagnozed throughout the world. No proper treatment of this disease has been found, medication is used only to stop heart diseases.

           

      

Hair pulling disorder

Patients of this bizarre mental condition have an intense urge to pull out his hair from scalp, eyebrows and eyelashes. It results in hair loss and formation of bare patches on scalp, which causes problems in work or social life. Main trigger for this abnormal act is anxiety, stress and tension. Psychic treatment for this condition is habit reversal training in which a bad habit is changed for a good one.

            

Bubonic plague

During 14th century, a strange disease spread across Europe and killed  30-60% population that is approximately 25 million people. This event is also known as "The black death", the main cause of which is considered bubonic plague. This highly dangerous and contagious disease is caused by an infectious bacteria which causes inflammation of "Lymph nodes" mainly in armpit and groin. Main symptoms are high fever, chills, headache and swollen lymph nodes known as "Buboes". Also spots are formed on skin which are later turned black. The bacteria mainly affects rodents, then fleas transmit this disease to human.

                        

Measles

Measles is a highly contagious disease which has killed enormous number of people in last 150 years. Its main cause is "Paramyxovirus" which causes infection of respiratory system. Major symptoms include redness of eyes, runny nose, fever and cough. This disease is transmitted to other people by sneezing, physical contact and coughing. Regular vaccination must be done to prevent this disease.