Erythema may occur at a dose of 2 Gy radiation or greater. Chronic
Chronic radiodermatitis occurs with chronic exposure to "sub-erythema" doses of ionizing radiation over a prolonged period, producing varying degrees of damage to the skin and its underlying parts after a variable latent period of several months to several decades. : 40   In the distant past this type of radiation reaction occurred most frequently in radiologists and radiographers who were constantly exposed to ionizing radiation, especially before the use of X-ray filters. : 40   Chronic radiodermatitis, squamous and
basal cell carcinomas may develop months to years after radiation exposure. : 130   Chronic radiodermatitis presents as atrophic indurated plaques, often whitish or yellowish, with telangiectasia, sometimes with hyperkeratosis. : 130

Other
Eosinophilic, polymorphic, and pruritic eruption associated with radiotherapy is a skin condition that occurs most often in women receiving cobalt radiotherapy for internal cancer. : 39–40 Radiation-induced erythema multiforme may occur when phenytoin is given prophylactically to neurosurgical patients who are receiving whole-brain therapy and systemic steroids. : 130

Delayed effects
Radiation acne is a cutaneous condition characterized by comedo-like papules occurring at sites of previous exposure to therapeutic ionizing radiation, skin lesions that begin to appear as the acute phase of radiation dermatitis begins to resolve. : 501 Radiation recall reactions occur months to years after radiation treatment, a reaction that follows recent administration of a chemotherapeutic agent and occurs with the prior radiation port, characterized by features of radiation dermatitis. Restated, radiation recall dermatitis is an inflammatory skin reaction that occurs in a previously irradiated body part following drug administration.
Beta emissions are also severely attenuated by air; their range generally does not exceed 6 feet (1.8 m) and intensity rapidly diminishes with distance.The eye lens seems to be the most sensitive organ to beta radiation, even in doses far below maximum permissible dose. Safety goggles are recommended to attenuate strong beta.Beta burns can occur also to plants. An example of such damage is the Red Forest, a victim of the Chernobyl accident. Careful washing of exposed body surface, removing the radioactive particles, may provide significant dose reduction. Exchanging or at least brushing off clothes also provides a degree of protection. If the exposure to beta radiation is intense, the beta burns may first manifest in 24–48 hours by itching and/or burning sensation that last for one or two days, sometimes accompanied by hyperaemia. After 1–3 weeks burn symptoms appear; erythema, increased skin pigmentation (dark colored patches and raised areas), followed by epilation and skin lesions. Erythema occurs after 5–15 Gy, dry desquamation after 17 Gy, and bullous epidermitis after 72 Gy. Chronic radiation keratosis may develop after higher doses. Primary erythema lasting more than 72 hours is an indication of injury severe enough to cause chronic radiation dermatitis. Edema of dermal papillae, if present within 48 hours since the exposition, is followed by transepidermal necrosis. After higher doses, the malpighian layer cells die within 24 hours; lower doses may take 10–14 days to show dead cells.