Serious Illness and Self-Employment Tax

Medical Expense Deduction When Costs Are Catastrophic

Section 213 allows you to deduct unreimbursed medical expenses that exceed 7.5% of your adjusted gross income. When serious illness reduces your income and increases your expenses simultaneously, the math shifts dramatically in your favor.

Consider someone whose income drops from $85,000 to $38,000 due to cancer treatment while their medical expenses hit $32,000. At $85,000 AGI, the 7.5% floor would be $6,375 -- deductible medical expenses of $25,625. At $38,000 AGI, the floor drops to $2,850 -- deductible medical expenses of $29,150. The lower income means more of your medical costs become deductible.

Qualifying expenses include: surgery, chemotherapy, radiation, hospital stays, prescription drugs, medical equipment, prostheses, wigs (for cancer patients -- Rev. Rul. 62-189), therapy (physical, occupational, mental health), transportation to treatment (67 cents/mile in 2026 or actual costs), lodging while away from home for treatment ($50/night cap per person), health insurance premiums you pay, and long-term care services. If you modify your home for medical reasons (wheelchair ramp, widened doorways), the cost minus any increase in property value is deductible.

You can deduct medical expenses exceeding 7.5% of your income, including treatment costs, prescriptions, medical travel, lodging for treatment, and medically necessary home modifications. (IRC Section 213(a) (deduction); IRC Section 213(d)(1) (definition of medical care); Rev. Rul. 62-189 (wigs for disease-related hair loss))

HSA as Triple-Tax-Advantaged Treatment Fund

If you had a High Deductible Health Plan (HDHP) before your diagnosis and contributed to a Health Savings Account, that HSA becomes your most tax-efficient way to pay treatment costs. Contributions are tax-deductible (or pre-tax if through payroll), growth is tax-free, and withdrawals for qualified medical expenses are tax-free. That's three layers of tax benefit on the same dollar.

For 2026, the HDHP minimum deductible is $1,650 (self-only) or $3,300 (family). HSA contribution limits are $4,300 (self-only) or $8,550 (family), with a $1,000 catch-up if you're 55 or older. If you're diagnosed mid-year, you can still make a full-year contribution for any month you were HSA-eligible on the first day of that month.

Important: once you enroll in Medicare (which happens automatically at 65, or earlier if you receive SSDI for 24 months), you can no longer contribute to an HSA. But you can still withdraw from an existing HSA tax-free for medical expenses indefinitely. If you're under 65 and applying for SSDI, be aware that SSDI eligibility backdates and Medicare coverage begins 24 months after your disability onset date -- this can retroactively end your HSA contribution eligibility.

Health Savings Account contributions are tax-deductible, grow tax-free, and can be withdrawn tax-free for medical expenses -- but you must have a qualifying high-deductible health plan and cannot be enrolled in Medicare. (IRC Section 223 (HSA rules); IRC Section 223(b) (contribution limits); IRC Section 223(b)(7) (Medicare ineligibility))

Penalty Relief and Filing Extensions for Illness

The IRS recognizes serious illness as reasonable cause for penalty abatement under IRM 20.1.1.3.2.1. If you missed filing or payment deadlines because you were hospitalized, undergoing treatment, or incapacitated, the IRS should remove penalties upon request with documentation.

You'll need: a letter explaining the illness and its timeline, medical documentation (a letter from your oncologist or treating physician stating dates of incapacity), and evidence that you filed/paid as soon as you were able. The standard is that you exercised 'ordinary business care and prudence' -- meaning you handled your tax obligations as quickly as your medical situation allowed.

Separately, the estimated tax underpayment penalty can be waived entirely under IRC Section 6654(e)(3)(A) if you became disabled during the tax year and the underpayment was due to the disability. File Form 2210, check Box A in Part II, and attach medical documentation. This is a statutory waiver, not a discretionary one -- if you qualify, the IRS must grant it.

Automatic filing extensions (Form 4868) give you until October 15, and if you're outside the US for medical treatment or too ill to file even by October, you can request additional time by letter. Interest still accrues on unpaid tax, but penalty-free breathing room matters when you're in treatment.

Serious illness is grounds for removing late-filing and late-payment penalties, and the estimated tax penalty must be waived if disability caused the underpayment. (IRM 20.1.1.3.2.1 (serious illness as reasonable cause); IRC Section 6654(e)(3)(A) (estimated tax waiver for disability); Form 2210 Part II)

SSDI, SGA Limits, and Remaining Self-Employment Income

If your illness qualifies you for Social Security Disability Insurance (SSDI), you can still earn some self-employment income without losing benefits -- but you must stay below the Substantial Gainful Activity (SGA) threshold: $1,620/month ($19,440/year) for non-blind individuals in 2026.

During a Trial Work Period (up to 9 months within a rolling 60-month window), you can earn any amount without losing SSDI benefits. A trial work month is any month you earn above $1,110 (2026). After the trial work period ends, any month you exceed SGA triggers a potential benefit cessation, though there's a 36-month extended eligibility period where benefits resume automatically in any month you drop below SGA.

The interaction with self-employment tax matters: SSDI benefits are not subject to self-employment tax, but any Schedule C income is. If you're earning $15,000/year from reduced freelance work while receiving $24,000/year in SSDI, you pay SE tax on the $15,000 but not the $24,000. Your total income is $39,000, but only the $15,000 flows through Schedule C.

Form 2848 (Power of Attorney) lets you authorize a spouse, family member, CPA, or enrolled agent to communicate with the IRS and handle tax matters on your behalf during treatment. This is essential if you'll be incapacitated for extended periods.

You can receive SSDI and still earn limited self-employment income below the Substantial Gainful Activity threshold without losing benefits. (Social Security Act Section 223(d)(4) (SGA); 20 CFR 404.1574 (SGA evaluation for self-employed); Form 2848 (POA))