Purpura

What is it?

Purpura refers to red, purple, or brown discolorations of the skin caused by bleeding from small blood vessels (capillaries) into the skin or mucous membranes. The defining characteristic of purpura is that it does NOT blanch (fade) when pressed — unlike erythema (simple redness), which disappears under pressure. This non-blanching feature indicates that blood has escaped from the vessels into the surrounding tissue. You can test this at home using the "glass test": press a clear glass firmly against the skin — if the discoloration persists, it is purpura.

Purpura is classified by size:

• Petechiae: Tiny spots, less than 2 mm (pinpoint size)
• Purpura: Spots between 2 mm and 1 cm
• Ecchymoses: Larger patches over 1 cm (bruises)

What does it look like?

Purpura has characteristic features:

• Color: Initially red or dark red, evolving through purple, blue-brown, and finally yellowish-green as the blood is reabsorbed (similar to bruise progression)
• Surface: Flat and level with the skin surface (non-palpable) in most cases, but raised and palpable when caused by vasculitis (inflamed blood vessels)
• Non-blanching: Does NOT fade when pressed — this is the key distinguishing feature
• Size: From pinpoint petechiae to large ecchymoses
• Shape: Spots may be round, irregular, or linear (in trauma)
• Clustering: May appear scattered or in clusters

Where does it appear?

Purpura develops in characteristic locations depending on the cause:

• Lower legs: Leukocytoclastic vasculitis, Henoch-Schonlein purpura (gravity-dependent areas)
• Shins and forearms: Senile (actinic) purpura in elderly patients (thin, sun-damaged skin)
• Trunk and extremities: Thrombocytopenia (low platelets), drug reactions
• Widespread: Meningococcemia (medical emergency), disseminated intravascular coagulation
• Gums and mucous membranes: Severe thrombocytopenia
• Around the eyes: Amyloidosis (periorbital purpura after minor straining)

Associated features

Purpura may be accompanied by:

• Fever (infections such as meningococcemia — emergency)
• Joint pain and swelling (vasculitis, Henoch-Schonlein purpura)
• Abdominal pain (Henoch-Schonlein purpura)
• Easy bruising or prolonged bleeding (thrombocytopenia, coagulopathy)
• Nosebleeds or gum bleeding (platelet disorders)
• General feeling of being unwell (systemic conditions)
• Palpable (raised) purpura (indicates vasculitis)
• Progression in size or number of spots

When to see a doctor

Seek IMMEDIATE medical attention for:

• Rapidly spreading purpura with fever (possible meningococcemia or sepsis — life-threatening emergency)
• Widespread petechiae or purpura with general unwellness (possible disseminated intravascular coagulation)
• Purpura with severe headache, stiff neck, and confusion (possible meningitis)

Seek prompt medical evaluation for:

• Any new, unexplained purpura — always needs evaluation
• Palpable (raised) purpura on the legs (possible vasculitis)
• Purpura accompanied by joint pain, abdominal pain, or blood in urine
• Easy and excessive bruising without clear cause
• Purpura after starting new medication (possible drug-induced thrombocytopenia)
• Petechiae in children with fever (always investigate to exclude meningococcal infection)