What is the likely diagnosis for a 22-year-old male with microcytic (Mean Corpuscular Volume (MCV)) hypochromic (Mean Corpuscular Hemoglobin (MCH), Mean Corpuscular Hemoglobin Concentration (MCHC)) anemia and elevated Red Cell Distribution Width (RDW) presenting with abnormal bruising?

Likely Diagnosis: Iron Deficiency Anemia with Urgent Need for GI Evaluation

This 22-year-old male almost certainly has iron deficiency anemia (IDA), and the abnormal bruising raises critical concern for an underlying bleeding disorder or severe coagulopathy from occult gastrointestinal blood loss—he requires immediate complete blood count with platelet count, coagulation studies, serum ferritin, and comprehensive gastrointestinal evaluation to exclude malignancy. 1, 2

Why Iron Deficiency Anemia is the Primary Diagnosis

The laboratory pattern is pathognomonic for IDA:

• Low MCV + elevated RDW (>14%) has 91.4% accuracy for iron deficiency anemia, distinguishing it from thalassemia trait which typically shows normal or only slightly elevated RDW 1, 2
• The elevated RDW reflects heterogeneous red cell populations as iron stores become progressively depleted, creating a distinctive signature 2
• Low MCH and MCHC confirm hypochromia, characteristic of iron deficiency 3, 4

Critical Red Flag: Abnormal Bruising

The bruising is NOT a typical feature of uncomplicated iron deficiency anemia and demands immediate investigation for:

Thrombocytopenia from Massive Blood Loss

• Severe ongoing GI bleeding can deplete platelets 1
• Check complete blood count with platelet count immediately 4

Coagulopathy

• Obtain PT/INR and aPTT to exclude bleeding disorders 1
• Consider von Willebrand disease or other inherited coagulopathies in a young male with bruising 2

Concurrent Hematologic Malignancy

• Leukemia or myelodysplastic syndrome can present with both anemia and thrombocytopenia 2
• The bruising may indicate bone marrow pathology beyond simple iron deficiency 4

Immediate Diagnostic Workup

Confirm Iron Deficiency

• Serum ferritin is the single most powerful test: ferritin <30 μg/L confirms iron deficiency in the absence of inflammation 1, 2
• Ferritin <12 μg/dL is diagnostic of iron deficiency 3, 2
• If inflammation present (check CRP), ferritin up to 100 μg/L may still indicate iron deficiency 1, 2
• Transferrin saturation <30% supports the diagnosis 3, 4

Evaluate for Bleeding Source

All adult men with confirmed iron deficiency require complete gastrointestinal evaluation regardless of symptom presence or anemia severity 1, 2:

• Upper endoscopy with mandatory small bowel biopsies to exclude malignancy and detect celiac disease (present in 2-3% of IDA patients) 3, 1, 2
• Colonoscopy or CT colonography to exclude colonic cancer/polyps 2
• Document NSAID and aspirin use—these medications cause occult GI bleeding 1, 2

Common GI Sources in Young Men

• NSAID use (most common) 3, 2
• Inflammatory bowel disease (Crohn's disease, ulcerative colitis) 3, 2
• Celiac disease 3, 1
• Angiodysplasia 3, 2
• Less common: gastric cancer, colonic polyps/cancer, Meckel's diverticulum 3, 2

Treatment Algorithm

Immediate Management

1. Stop NSAIDs and anticoagulants if being used 1, 2
2. Initiate oral iron immediately once ferritin confirms deficiency: ferrous sulfate 200 mg (65 mg elemental iron) three times daily 1
3. Add ascorbic acid (vitamin C) to enhance absorption 1

Expected Response

• Hemoglobin should rise ≥10 g/L (≥1 g/dL) within 2 weeks—this confirms iron deficiency 1
• If no response within 2-4 weeks, consider non-compliance, ongoing blood loss (most common), or malabsorption 1, 4
• Continue treatment for 3-6 months after hemoglobin normalizes to replete iron stores 1, 2, 4

If Oral Iron Fails

• Switch to intravenous iron (iron sucrose or iron gluconate) with expected hemoglobin increase of at least 2 g/dL within 4 weeks 1

Critical Pitfalls to Avoid

• Never assume dietary deficiency alone in an adult male—GI blood loss is the most common cause and requires investigation to exclude malignancy 1, 2
• Do not dismiss mild anemia—severity does not correlate with likelihood of serious underlying disease 3, 2
• The bruising is atypical and must be explained—obtain platelet count and coagulation studies before attributing everything to iron deficiency 1, 4
• Combined deficiencies (iron plus B12 or folate) may mask typical findings—the elevated RDW is particularly valuable in detecting these 3, 2, 4