What could be causing my cold hands and feet, psoriasis, and eczema, given my normal vitamin and mineral levels, negative celiac test, and thyroid-stimulating hormone (TSH) levels at the higher end of the normal range, and how can I manage these symptoms?

Cold Extremities with Psoriasis and Eczema: Evaluation and Management

Primary Assessment

Your cold hands and feet are most likely related to peripheral vasoconstriction from subclinical hypothyroidism (TSH 3-4 is at the upper limit of normal), combined with the systemic inflammatory burden from your psoriasis and eczema. The temporary improvement after strength training suggests a vascular/circulatory component rather than a fixed metabolic defect.

Thyroid Considerations

Your TSH of 3-4 mU/L sits at the higher end of the reference range, which warrants closer attention given your symptoms:

• Cold intolerance is a cardinal feature of hypothyroidism, even when TSH remains within the "normal" range 1
• The American Heart Association recognizes that hypothyroidism presents with cold skin and delayed reflexes, which aligns with your cold extremities 1
• Patients with psoriasis have a significantly increased risk of thyroid dysfunction (OR 1.34-1.38 for hypothyroidism) 2
• Studies show that psoriasis patients frequently have low T4 and/or T3 with normal or high-normal TSH 2

Recommendation: Request a complete thyroid panel including free T3 (not just TSH and free T4) from your endocrinologist. Your current FT3 of 5.8 and FT4 of 16 need context with their reference ranges, but the pattern of symptoms suggests possible subclinical hypothyroidism or thyroid autoimmunity 2.

Psoriasis-Thyroid Connection

The relationship between your skin conditions and thyroid function is well-established:

• Autoimmune thyroid disease occurs at higher rates in psoriasis patients (OR 1.42-2.05), particularly Hashimoto's thyroiditis (OR 1.47-2.09) 2
• Female patients with psoriasis show higher rates of positive antithyroperoxidase antibodies (TPOAb), though this occurs in males as well 2
• Request TPOAb and antithyroglobulin antibody testing if not already done, as thyroid autoimmunity may be present even with "normal" TSH 2, 3

Dermatologic Management

Your psoriasis and eczema require optimization regardless of thyroid status:

Skin Barrier Protection

• Avoid all soaps and detergents, as these remove natural lipids and worsen dry skin in atopic conditions 1, 4
• Use dispersible cream as a soap substitute for cleansing 1
• Apply emollients immediately after bathing to provide a surface lipid film that retards water loss 1
• Avoid extremes of temperature and wear cotton clothing rather than wool next to skin 1

Trigger Identification

• Bacterial infection may be causing flares if you notice crusting or weeping lesions 4
• Consider patch testing for allergic contact dermatitis, particularly given your hand and potential facial involvement 4
• The British Medical Journal notes that deterioration in previously stable eczema often indicates secondary infection or contact dermatitis 1

Topical Treatment

• Topical corticosteroids remain the mainstay of eczema treatment when used appropriately 1
• Use the least potent preparation needed to control the condition 1
• For psoriasis, consider short-contact dithranol therapy (15-45 minutes daily) if topical steroids are insufficient 1

Cardiovascular Screening

Given your psoriasis, you require cardiovascular risk assessment:

• The American Academy of Dermatology recommends screening for hypertension, diabetes, and hyperlipidemia in all psoriasis patients 1
• Patients with psoriasis have 34% prevalence of metabolic syndrome versus 26% in controls (OR 1.50) 1
• Your risk scores should be multiplied by 1.5 given your psoriasis severity requiring systemic consideration 1
• Cold extremities can also indicate peripheral vascular disease, which occurs at higher rates in psoriasis patients 1

Exercise Response Explanation

The temporary improvement in your cold extremities after strength training suggests:

• Vascular reactivity rather than fixed metabolic dysfunction - exercise increases peripheral blood flow and temporarily improves circulation
• This pattern is consistent with peripheral vasoconstriction from either subclinical hypothyroidism or systemic inflammation 1
• Regular exercise should be encouraged as part of lifestyle modification for both cardiovascular health and psoriasis management 1

Immediate Action Plan

1. Request complete thyroid panel including free T3, TPOAb, and antithyroglobulin antibodies from your endocrinologist 2, 3
2. Optimize skin barrier function with soap-free cleansing and intensive emollient therapy 1, 4
3. Screen for cardiovascular risk factors including fasting lipids, glucose, and blood pressure if not recently done 1
4. Consider bacterial culture if any crusting or weeping is present on your skin lesions 1, 4
5. Evaluate for contact dermatitis through patch testing, especially if hand involvement is prominent 4

Common Pitfalls to Avoid

• Do not dismiss TSH in the 3-4 range as "normal" when clinical symptoms of hypothyroidism are present, particularly in psoriasis patients who have higher thyroid dysfunction rates 2
• Do not perform broad panel allergy testing without specific history of reactions, as positive tests may reflect sensitization without clinical relevance 4
• Do not neglect secondary infections as causes of sudden eczema deterioration 1, 4
• Do not continue using regular soaps despite supplementing with emollients - the damage from lipid removal outweighs the benefit of moisturizers 1