Radiation dermatitis - Skin
Radiosensitizing agents act concomitantly to worsen skin damage. Pathophysiologic mechanisms leading to radiation-induced dermatitis can be classified as acute or chronic.
Acute Radiation Dermatitis
This occurs within 90 days of exposure. The patient may have changes ranging from faint erythema and dry desquamation to skin necrosis and ulceration, depending on the severity of the reaction. The National Cancer Institute has developed a 4 stage criteria for the classification of acute radiation dermatitis:
- Grade 1 – Faint erythema or dry desquamation.
- Grade 2 – Moderate to brisk erythema or patchy, moist desquamation confined to skin folds and creases. Moderate edema.
- Grade 3 – Confluent, moist desquamation greater than 1.5 cm diameter, which is not confined to the skin folds. Pitting edema.
- Grade 4 – Skin necrosis or ulceration of full thickness dermis.
This is an extension of the acute process and involves further inflammatory cytokines. Long-lasting impairment of the skin's ability to heal can be due to compromised cellular dysfunction. Fibroblasts may be permanently altered, leading to atrophy and fibrosis.
Onset may occur from 15 days to 10 years after the beginning of the procedure. There is no increased predilection for radiation injuries between men and women. The predominance in males of radiation dermatitis merely reflects the higher incidence of coronary artery disease and subsequent increased use of fluoroscopic procedures for therapeutic purposes.
This is a well-documented phenomenon that occurs at sites of previous radiation therapy, after an antineoplastic agent (eg, methotrexate, etoposide) is given. The reaction may occur weeks to years after radiation. As in acute radiation dermatitis, it is graded according to the severity of the cutaneous reaction and ranges from erythema to necrosis, ulceration, and hemorrhage. It tends to occur when cytotoxic agents are used following the completion of radiotherapy. Radiation recall has also been seen after the use of drugs such as nonsteroidal antiestrogens, interferon alpha-2b, and antituberculosis drugs.
Risk factors for radiation dermatitis in the general population are as follows:
- Poor nutritional status
- Problems with skin integrity
- Overlapping skin folds
- Prolonged or multiple procedures requiring radiation exposure.
- Increased exposure, especially in obese patients. (Larger patients require higher doses of radiation and are, therefore, more susceptible to developing skin changes.).
- Total radiation doses of greater than 55 Gy, or large individual doses per fraction (greater than 3-4 Gy per dose).
- Concurrent cetuximab therapy in patients receiving radiation for head and neck malignancies.
- Connective tissue diseases (systemic lupus erythematosus, scleroderma, or mixed connective tissue diseases). Peripheral blood lymphocytes from patients with rheumatoid arthritis, systemic lupus erythematosus, and polymyositis are more radiosensitive and exhibit greater DNA damage after irradiation. Thus, the presence of connective tissue diseases is a contraindication to radiation therapy.
- Diseases with reduced cellular DNA capability, such as hereditary nevoid basal cell carcinoma.
- Diseases involving chromosomal breakage syndromes, like Fanconi's anemia and Bloom syndrome.
- Homozygosity for the ataxia telangiectasia gene.
- Infectious diseases – Patients with HIV show a reduced tolerance of the skin and mucous membranes to treatment. Not only do they develop cutaneous changes at lower doses but also more significant systemic problems.
- Diabetes mellitus
- Radiosensitizing drugs (eg, paclitaxel or docetaxel) given before or up to 7 days after radiation therapy increase cellular damage.
L58.9 – Radiodermatitis, unspecified
49084001 – Radiation dermatitis
- Allergic contact dermatitis
- Cellulitis / erysipelas
- Carcinoma erysipeloides
- Primary / autoimmune blistering disease (eg, bullous pemphigoid)