Hypersensitivity Reactions - Know your basics!
ð€What is Hypersensitivity?
The immune system protects the human body against disease by dispatching a bunch of immune cells whenever the body encounters foreign material or antigens.Â
These immune cells or effector cells elicit an inflammatory response in order to remove or eliminate the foreign antigen without causing much damage to the host.Â
ð¡However, under certain conditions, the host may elicit an exaggerated or an inappropriate immune response to a foreign antigen causing much damage to host tissues. This exaggerated or inappropriate immune response is termed hypersensitivity.Â
ð€§Types of Hypersensitivity reactions?
There are four types of hypersensitivity them being Type I, Type II, Type III and Type IV hypersensitivity.
Type I hypersensitivity is also termed allergy or atopy and immediate hypersensitivity since symptoms manifest rapidly within minutes to hours.
Type II hypersensitivity is an antibody mediated cytotoxic reaction, where cell damage is a result of antibodies binding to antigens on cell surfaces.
Type III hypersensitivity is an immune complex disease, where the tissue damage is a result of the inflammation induced by antigen-antibody complexes also called immune complexes.
Type IV hypersensitivity reaction is a T-cell mediated response primarily caused by CD4+ T cells, though these reactions can also be caused by CD 8+ T cells. Type IV hypersensitivity is also called delayed type hypersensitivity due to its delayed onset of reaction.
ð¡Remember,
It is a prerequisite to have an awareness/knowledge of the basics of General Pathology, in order to better comprehend the pathology of oral diseases. The basics would immensely improve your understanding of Oral Pathology and Medicine. This could help you in two ways.
If and when you are preparing for NEET/NBDE/NDBE (or any entrance exam for that matter), an understanding of basics would immensely benefit you.
What if you want to specialize in Oral Pathology? I tell you from experience, the basics of (General) Pathology would go a long way in making you a competent Oral Pathologist.
ð¡I say this because I have seen so many students without a sound understanding of basic Pathology (heck even Oral Pathology), struggling to understand concepts in Oral Pathology. The same goes for histology, both (general and oral), but that topic is for another blog post! I know these subjects can be very difficult to comprehend. I get it. Thatâs why I try to make stuff lighthearted, so they are easier to understand :)
Learning and understanding âhypersensitivity reactionsâ (Type I - Type IV) could be overwhelming. Honestly, I found it very difficult to comprehend these topics during my UG days. My understanding was all âhotchpotchâ! I really wish I had resources that would have made my life easy during those days.
In fact, thatâs why I created videos for all four hypersensitivity reactions! I had great fun making them and they make learning easy and light hearted. I bet youâll love them. I have them all on the HackDentistry-YouTube channel to watch for free!
ðœ Free Videos!
ðYou could dig deeper into the topic
If ever, you want to go deep into Hypersensitivity and get access to the scripts of these videos we have some great notes, all of which are available on our Revision Ninja - Oral Pathology and Medicine Course bundle!
Type I Hypersensitivity (Video available on YouTube for free, Video & Notes available on our website)
Type II Hypersensitivity (Video available on YouTube for free, Video & Notes available on our website)
Type III Hypersensitivity (Video available on YouTube for free, Video & Notes available on our website)
Type IV Hypersensitivity (Video available on YouTube for free, Video & Notes available on our website)
ðOther basic topics in HackDentistry
Common histopathology terms (Note with sketches)
Inclusion bodies and modified cells in diseases (Table)
Stratified squamous epithelium (Note & Video)
Lymphocytes (Note & Video, preview video available on YouTube)
Inflammation (Note & Video, video also available on YouTube)
Mediators of Inflammation (Note & Video, video also available on YouTube)
Mediators of Inflammation - Vasoactive amines and Eicosanoids (Note with sketches)
Apoptosis (Note & Video, video also available on YouTube)
Phagocytosis (Note & Video, video also available on YouTube)
Antigen recognition by T - cells (Note & Video, video also available on YouTube)
ð¡Watch this space! We would be updating this section with more topics!
ð¡Note
Apart from Notes, you could also get access to numerous MCQs and Videos with English captions/subtitles on various topics in Oral Pathology and Medicine.
ðOther study resources on HackDentistry!
And hey, by the way, please do give HackDentistry a shout-out to your friends and colleagues, would you? Would really appreciate it! Cheers and happy reading :)
Best
Dr.Sanketh from Team HackDentistry