Bleeding Under the Skin
Conditions of the skin, subcutaneous tissue, vascular wall, and blood
may all be associated with bleeding under the skin or purpura, thus both
anatomy and physiology must be used to develop this differential
(Table 12). The skin may hemorrhage from infections such as
smallpox, scabies, chickenpox, and measles, especially when the patient
traumatizes the area to relieve the itching. A bug bite also may
cause hemorrhage by this means. Focal and
metastatic neoplasms may cause hemorrhage in the skin, whereas degeneration
of the skin may lead to senile purpura. Trauma is by far the most common
cause of hemorrhage of the skin.
The subcutaneous tissue is distinguished separately, so that one will
recall the Ehlers–Danlos syndrome and pseudoxanthoma elasticum. The
vascular wall may be damaged by numerous etiologies. The most important
infectious etiologies are subacute bacterial endocarditis and
meningococcemia, but typhoid fever, Weil disease, and Rocky Mountain spotted
fever should not be forgotten. Systemic neoplasms that infiltrate the
vascular wall (such as leukemia) are significant causes, but these usually
cause purpura by inducing thrombocytopenia. Vascular degeneration and
deficiency diseases (such as scurvy) are uncommon causes of purpura. Toxic
conditions are more likely to be related to bone marrow suppression of
platelets. Congenital lesions such as hereditary telangiectasias are
important to remember.
Most important of all are the allergic and autoimmune disorders, because
something can be done to alleviate the condition (e.g., steroids or
immunosuppressants). Henoch–Schönlein purpura is a significant
form of allergic vasculitis, but periarteritis nodosa is important as well.
Trauma is just as important here as in the skin. Thus, a ruptured varicose
vein, crush injury, whooping cough, or contusions are important causes of
purpura. Endocrine disorders also cause vascular purpura (as in Cushing
syndrome).
Disorders of the blood figure prominently in purpura. Significant
among these are the numerous disorders that cause suppression or increased
destruction of platelets. Toxic disorders such as gold injections,
salicylate ingestion, potassium iodide, quinidine, ergot, and chloral
hydrate are just a few of these. It is best to assume that any drug may
cause purpura until proven otherwise. Leukemic overgrowth of the bone marrow
may cause purpura because of thrombocytopenia, but any neoplasm that
infiltrates the marrow (myelophthisic anemia) must be considered. Autoimmune
disease suggests the purpura of idiopathic thrombocytopenic purpura (ITP)
and lupus erythematosus.
Degenerative disorders bring to mind aplastic anemia, although this is often
caused by drug suppression of the bone marrow. Congenital disorders are more
often the cause of coagulation disorders such as hemophilia, but coagulation
disorders are often associated with heparin and dicoumarin therapy as well.
Trauma and endocrine disorders do not figure as prominently here. There may
still be a platelet disorder even though the platelet count is normal. Thus,
one should investigate for hereditary thrombasthenia and salicylate
toxicity, among other things, by doing a clot retraction test as a screen.
Approach to the Diagnosis
The clinical approach to purpura involves taking a drug history and a
good family history, and ordering appropriate coagulation studies,
tourniquet testing, and other tests. Referral to a hematologist is wise in
obscure cases.
Other Useful Tests
-
Complete blood count (CBC) (aplastic anemia, leukemia, collagen
disease)
-
Sedimentation rate (systemic infection, inflammation)
-
Coagulation time (hemophilia, disseminated intravascular
coagulation [DIC])
-
Partial thromboplastin time (hemophilia, DIC)
-
Bleeding time (vasculitis, vascular purpura)
-
Prothrombin time (liver disease, drug toxicity, etc.)
-
Platelet count (aplastic anemia, leukemia, collagen disease, ITP)
-
Rumpel–Leede test (vascular purpura, ITP, collagen disease)
-
Thromboplastin generation test (DIC, hemophilia)
-
Bone marrow examination (leukemia, aplastic anemia, myelophthisic
anemia)
-
Antinuclear antibody (ANA) analysis (collagen disease)
-
Blood cultures (septicemia, DIC)
-
Coombs test (autoimmune disorders)
-
Monospot test (infectious mononucleosis)
-
CT scan of abdomen (neoplasm, splenomegaly)
-
Skin biopsy (Ehlers–Danlos syndrome, etc.)
-
Muscle biopsy (collagen disease)
-
Liver–spleen scan (metastasis, splenomegaly)
-
Bone scan (metastatic neoplasm)
Pictures
Book Source Details
- Book Title: Differential Diagnosis in Primary Care
- Author(s): R. Douglas Collins MD, FACP
- Year of Publication: 2007
- Copyright Details: Differential Diagnosis in Primary Care, Copyright © 2007 Lippincott Williams & Wilkins.
Other Book Chapters Related to Bleeding under skin
Read excerpts from these other book chapters related to Bleeding under skin:
Medical Books Excerpts
- Purpura
- "In a Page: Signs and Symptoms" (2004)
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- Purpura
- "In A Page: Pediatric Signs and Symptoms" (2007)
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- Purpura
- "Handbook of Signs & Symptoms (Third Edition)" (2006)
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- Purpura
- "Professional Guide to Signs & Symptoms (Fifth Edition)" (2006)
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- Thrombocytopenia
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
- Purpura
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
- Purpura
- "Nursing: Interpreting Signs and Symptoms" (2007)
- [ read ]
Copyright Details: Differential Diagnosis in Primary Care, Copyright © 2008 Williams & Wilkins.
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