Erythema nodosum is the MCC of inflammation of subcutaneous fat (panniculitis).
 - it may be associated with tuberculosis, leprosy, certain drugs (sulfonamides), and is commonly a harbinger of coccidioidomycosis and sarcoidosis.
 - commonly presents on the lower extremities with exquisitely tender, raised erythematous plaques and nodules.
 - self-limited disease.

Hematological examination

This is a method by which abnormalities of the cells of the blood and their precursors in the bone marrow are investigated to diagnose the different kinds of anemia & leukemia.

CHRONIC INFLAMMATlON

When the inflammatory reaction instead of subsiding after the acute phase (or without entering an acute phase), persists as a smouldering lesion, it is called chronic inflammation. .

Characteristics

• Predominantly mononuclear response.
• Inflamation.and..repair going on simultaneously.
• Usually results in more prominent-scarring.

Causes:

Chronicity may be due to :

- Defective defence mechanisms.

- Persistence of injurious agent.

(a) Certain organisms resist phagocytosis and destruction e.g tubercle bacillus, fungi

(b) insoluble particulate matter e.g., crystals. fibres suture materials.

(c) Constants supply of causative agent as in autoimmune disease where body reacts against its own tissues.

- Defective healing.

Granulomatous inflammation

It is a type of chronic inflammation characterised by localised collections of histiocytes.

These cells are usually accompanied by lymphocytes, fibroblasts and giant cells also.

Granulomas are characteristically seen in diseases like tuberculosis. syphilis, leprosy, sarcoidosis, fungal infections etc. In some of these, the lesion is morphologically distinct  enough to point to the type of underlying disease. These are sometimes called' specific' granulomas. Granulomas can also be elicited by particulate, insoluble foreign material e.g. granuloma, suture granuloma, cholesterol granuloma (organising haemorrhages).

Hepatic failure 
Etiology. Chronic hepatic disease (e.g., chronic active hepatitis or alcoholic cirrhosis) is the most common cause of hepatic failure although acute liver disease may also be responsible.

- Widespread liver necrosis may be seen with carbon tetrachloride and acetaminophen toxicity. Widespread steatosis is seen in Reye's syndrome, a cause of acute liver failure most often seen in children with a recent history of aspirin ingestion for an unrelated viral illness. 
- Massive necrosis may also be seen in acute viral hepatitis, after certain anesthetic agents, and in shock from any cause. 

Clinical features. Hepatic failure causes jaundice, musty odor of breath and urine, encephalopathy, renal failure (either by simultaneous toxicity to the liver and kidneys or the hepatorerial syndrome), palmar erythema, spider angiomas, gynecomastia , testicular atrophy 

Varicose Veins  
- are abnormally dilated, tortuous veins produced by prolonged increase in intraluminal pressure and loss of vessel wall support. 

- The superficial veins of the leg are typically involved  

-venous pressures in these sites can be markedly elevated -> venous stasis and pedal edema (simple orthostatic edema)

-Some 10% to 20% of adult males and 25% to 33% of adult females develop lower extremity varicose  veins  

RISK FACTORS 
-> obesity  
-> Female gender  
-> pregnancy.  
-> familial tendency (premature varicosities results from imperfect venous wall development) 

 Morphology
 
- wall thinning  
- intimal fibrosis in adjacent segments 
- spotty medial calcifications (phlebosclerosis) 
- Focal intraluminal thrombosis 
- venous valve deformities (rolling and shortening) 

COMPLICATIONS
 
- stasis, congestion, edema, pain, and thrombosis 
- chronic varicose ulcers 
- embolism is very rare. 

Group A Streptococcus
 - scarlet fever usually begins as a Streptococcal pharyngitis/tonsillitis and then develops an erythematous rash beginning on the trunk and limbs with eventual desquamation.
 - rash is due to elaboration of erythrogenic toxin by the organism
 - face is usually spared, but, if involved there is a characteristic circumoral pallor and the tongue becomes bright red, thus the term "strawberry tongue".
 - post-streptococcal immune complex glomerulonephritis is a possible sequela of scarlet fever.
 - Dick test is a skin test that evaluates immunity against scarlet fever; no response indicates immunity (anti-toxin antibodies present); erythema indicates no immunity.
 - impetigo due to Streptococcus pyogenes is characterized by honey colored, crusted lesions, while those with a predominantly bullous pattern are primarily due to Staphylococcus aureus.
 - cellulitis with lymphangitis ("red streaks") is characteristic of Streptococcus pyogenes.
 - hyaluronidase is a spreading factor that favors the spread of infection throughout the subcutaneous tissue unlike Staphylococcus aureus which generates coagulase to keep the pus confined.
 - erysipelas refers to a raised, erythematous ("brawny edema"), hot cellulitis, usually on the face that commonly produces septicemia, if left untreated.