http://derma.akademos.de/pdfdown/akadem ... ea6887.pdf
Phase 1: local infection of the skin
In the first phase of infection, the pathogen is deposited in
the skin by means of a tick bite. Once in the skin it begins to
reproduce.The pathogen has a long generation time,
spanning 20 to 30 hours which is why it reproduces only
slowly. Only after a latency period, which normally covers
about ten days (even with reinfection it is at least seven
days), there is a cellular and humoral immune response. All
cutaneous manifestations of borreliosis, from erythema
migrans to acrodermatitis,present with bluish-red areas of
skin caused by the migration of lymphocytes and plasma
cells, i.e., the cellular immune response of the skin.
Depending on the intensity of the cellular immune response,
typical erythema migrans (EM) or borrelial lymphocytoma
(BL) develops.The latter can occur alone or in
combination with EM. In rare instances, there is also a concomitant
reaction of the subcutaneous fatty tissue in the
form of panniculitis.
Phase 2: generalization of disease
After the pathogen multiplies in the skin, it migrates peripherally
from the site of the bite and at some point enters
the blood or lymphatic vessels. Borrelial organisms are thus
carried in the bloodstream and the generalization phase,
the second stage of disease, begins. Clinically, this stage is
characterized by generalized flu-like symptoms,myalgia,
headache, (sometimes) fever, night sweats, and palpitations.
Initial organ manifestations (carditis, neuritis, ophthalmitis,
etc. can also occur).Afterward there is a severe
immune response and the pathogen count drops drastically.
Only in collagen can Borrelia successfully evade the
immune response.There they persist and can trigger later
disease episodes after a secondary latency period of a
variously long duration.
Phase 3: chronic phase
Clinically the third stage of disease is characterized by
neuropathy, arthralgia, and myalgia, which are accompanied
during disease episodes by generalized symptoms
(mainly night sweats, occasionally fever). In general,any
area of the body may be affected. Acrodermatitis chronica
atrophicans may develop on the skin, often after a prolonged
course of disease lasting several. It is first apparent
during an inflammatory stage, and then after a longer
period develops into »cigarette paper-like« atrophy. This is
almost always accompanied by neuropathy and osteopathy.
Occasionally there are also the pathognomonic fibroid
nodules containing a high number of pathogens.
In all stages of disease, the pathogen can be cultivated
from infected tissue which underscores the character of a
chronic bacterial infection analogous to syphilis. In no
phase of borrelial infection does spontaneous healing
occur. This also parallels syphilis. In the following we focus
on disease manifestations involving the skin.