The culprit can be both a prescription drug or an over-the-counter medication.

Examples of common drugs causing drug eruptions are antibiotics and other antimicrobial drugs, sulfa drugs, nonsteroidal anti-inflammatory drugs (NSAIDs), biopharmaceuticals, chemotherapy agents, anticonvulsants, and psychotropic drugs. Common examples include photodermatitis due to local NSAIDs (such as piroxicam) or due to antibiotics (such as minocycline), fixed drug eruption due to acetaminophen or NSAIDs (Ibuprofen), and the rash following ampicillin in cases of mononucleosis.

Certain drugs are less likely to cause drug eruptions (rates estimated to be ≤3 per 1000 patients exposed). These include: digoxin, aluminum hydroxide, multivitamins, acetaminophen, bisacodyl, aspirin, thiamine, prednisone, atropine, codeine, hydrochlorothiazide, morphine, insulin, warfarin, and spironolactone.

It is estimated that 2—3 percent of hospitalised patients are affected by a drug eruption, and that serious drug eruptions occur in around 1 in 1000 patients.

Bullous drug reaction (also known as a "bullous drug eruption", "generalized bullous fixed drug eruption", and "multilocular bullous fixed drug eruption") most commonly refers to a drug reaction in the erythema multiforme group. These are uncommon reactions to medications, with an incidence of 0.4 to 1.2 per million person-years for toxic epidermal necrolysis and 1.2 to 6.0 per million person-years for Stevens–Johnson syndrome. The primary skin lesions are large erythemas (faintly discernible even after confluence), most often irregularly distributed and of a characteristic purplish-livid color, at times with flaccid blisters.

Because the eruption is transient and self-limiting, no treatment is indicated.

Erythema multiforme is frequently self-limiting and requires no treatment. The appropriateness of glucocorticoid therapy can be uncertain, because it is difficult to determine if the course will be a resolving one.

The treatment is (1) stop the offending drug (antibiotics), (2) symptomatic (fever), and (3) for complications (hepatitis).

The condition usually resolves on its own, and treatment is not required. Oral antihistamines or topical steroids may be used to decrease itching. Steroids do provide relief from itching, and improve the appearance of the rash, but they also cause the new skin that forms (after the rash subsides) to take longer to match the surrounding skin color. While no scarring has been found to be associated with the rash, scratching should be avoided. It's possible that scratching can make itching worse and an itch-scratch cycle may develop with regular scratching (that is, you itch more because you scratch, so you scratch more because you itch, and so on). Irritants such as soaps with fragrances, hot water, wool, and synthetic fabrics should be avoided. Lotions that help stop or prevent itching may also be helpful.

Direct sunlight makes the lesions resolve more quickly. According to this principle, medical treatment with ultraviolet light has been used to hasten resolution, though studies disagree whether it decreases itching or not. UV therapy is most beneficial in the first week of the eruption.

Oral erythromycin was effective in treating patients in one early trial, but a later study could not confirm these results. Since Human Herpes Virus 6 or Human Herpes Virus 7 has been hypothesized to be the cause, the antiviral drug Acyclovir may reduce length of duration and severity.

It can be treated with systemic antiviral drugs, such as aciclovir or valganciclovir. Foscarnet may also be used for immunocompromised host with Herpes simplex and acyclovir-resistant Herpes simplex.

Zirconium granulomas are a skin condition characterized by a papular eruption involving the axillae, and are sometimes considered an allergic reaction to deodorant containing zirconium lactate. They are the result of a delayed granulomatous hypersensitivity reaction, and can also occur from exposure to aluminum zirconium complexes. Commonly, zirconium containing products are used to relieve toxicodendron irritation. The lesions are similar to those from sarcoidosis, and commonly manifest four to six weeks after contact. They appear as erythrematous, firm, raised, shiny papules. Corticosteroids are used to ease the inflammation, but curative treatment is currently unavailable.

Generally, PLE resolves without treatment; also, PLE irritations generally leave no scar. However, in severe cases the use of steroids is necessary to help reduce inflammation and increase quality of life of the patient. There are also other therapies for patients who are severely impacted, such as light therapy to harden the skin's surface.

Acute generalized exanthematous pustulosis (AGEP) (also known as "pustular drug eruption" and "toxic pustuloderma") is a rare skin reaction that in 90% of cases is related to medication administration. AGEP is characterized by a sudden skin eruption that appears on average five days after the medication is started.

It is mediated by T cells.

In most patients, the condition lasts only a matter of weeks; in some cases it can last longer (up to six months). The disease resolves completely without long-term effects. Two percent of patients have recurrence.

Many suspected aetiologic factors have been reported to cause EM.

- Infections: Bacterial (including Bacillus Calmette-Guérin (BCG) vaccination, haemolytic "Streptococci", legionellosis, leprosy, "Neisseria meningitidis, Mycobacterium, "Pneumococcus, "Salmonella" species, "Staphylococcus" species, "Mycoplasma pneumoniae), "Chlamydial.

- Fungal (Coccidioides immitis)

- Parasitic ("Trichomonas" species, "Toxoplasma gondii), "

- Viral (especially Herpes simplex)

- Drug reactions, most commonly to: antibiotics (including, sulphonamides, penicillin), anticonvulsants (phenytoin, barbiturates), aspirin, antituberculoids, and allopurinol and many others.

- Physical factors: radiotherapy, cold, sunlight

- Others: collagen diseases, vasculitides, non-Hodgkin lymphoma, leukaemia, multiple myeloma, myeloid metaplasia, polycythemia

EM minor is regarded as being triggered by HSV in almost all cases. A herpetic aetiology also accounts for 55% of cases of EM major. Among the other infections, "Mycoplasma" infection appears to be a common cause.

Herpes simplex virus suppression and even prophylaxis (with acyclovir) has been shown to prevent recurrent erythema multiforme eruption.

Currently there is no cure for actinic prurigo, and treatment focuses on relieving the dermatologic symptoms, by way of topical steroid creams or systemic immunosuppressants.

Prescribed treatments include:

- topical creams such as Tacrolimus and Betamethasone.

- systemic immunosuppressants such as Prednisone.

- In some cases, Thalidomide has proven to be effective in controlling the symptoms of actinic prurigo.

All patients with AP are encouraged to minimize sun exposure, and to use strong sunscreen throughout the year, and even on cloudy or overcast days, as UVA light, unlike UVB light, is able to penetrate cloud cover and remains constant throughout the day.

Alternative treatment methods might include UV Hardening, Meditation and/or cognitive behavioral therapy. UV-A desensitization phototherapy has also been shown to be effective in cases.

Treatment is symptomatic.

Treatment does not require a doctor's attention unless the case is severe, with most affected using a topical anti-itch cream (diphenhydramine) and a cortisone solution (hydrocortisone). Do not scratch the area, and avoid any clothing that may irritate the affected area; scratching will result in localized swelling and intense itching.

Upon exiting the water, prompt removal of swim clothing (while it is still wet) followed by a warm sea-water shower largely negates the risk of Seabather's eruption even in endemic areas. A hot freshwater shower with soap (paying particular attention to the hair and areas covered by the suit) is a somewhat less-effective alternative if uncontaminated seawater is unavailable. The contaminated swimsuit should be machine washed with laundry soap and dried in warm air.

Animals can be affected as well, and a cortisone solution for humans can be used on dogs.

There is no cure for Schamberg's disease; however, the itching can be controlled by a cortisone cream, and Colchicine treatment has been successfully used to prevent recurrence of the symptoms. This condition is not life-threatening or a major health concern. The only problem that patients will encounter is the itching and discoloration of the skin. It is recommended that patients take a vitamin C supplement to promote collagen production, which will help make the skin look and feel healthier. To prevent further irritation of the lesions, patients should avoid food with artificial colors and preservatives. Some people can be allergic to preservatives, which can cause the body to initiate an allergic reaction by further irritating those lesions. Several research studies have indicated that Schamberg's disease can be controlled and the number of lesions can be reduced with use a drug called aminaphtone. This drug helps improve capillary fragility and it prevents and controls the purpuric lesions.

A patient with Schamberg's disease can live a normal and healthy life. Since there is no proven cure for this condition, the patient will have to endure the lesions on his or her skin. With appropriate treatments, the condition may get better. Although the skin lesions are not life-threatening, it may cause a cosmetic concern for some individuals. Skin lesions may cause psychological discomfort, where patients may require reassurance to help with stress and anxiety. There are a few rare cases of T-cell lymphoma that has developed from Schamberg's disease.This is not a cause for concern, since the risk factors associated with Schamberg's disease are relatively low.

Polymorphous light eruption (PLE), or polymorphic light eruption (PMLE), is a skin condition triggered by sunlight.

The cause of erythema toxicum is thought to be an activation of the immune system. Some neonates are more sensitive than others and develop erythematous spots all over the body. Another theory is hypersensitivity to detergents in bedsheets and clothing is sometimes suspected, but the connection remains unproven.

It is thought to be a benign condition that causes no discomfort to the infant. The rash will generally disappear spontaneously in about 2 weeks.

"Narrowband UVB therapy as an effective treatment for Schamberg's disease."

This research article proposed that narrowband UVB therapy can be considered as a treatment for pigmented purpura. A study was done on a 33 year old man who had a 3 month history of widespread pigmented purpura. Oral prescription of prednisolone and topical ointment helped controlled the purpuric eruptions, but when the medication was stopped, the rash recurred. Researchers placed the patient on a UV therapy for 5 months. The patient showed signs of improvement, where new purpuric eruptions stopped and some of the pigmented purpura disappeared. However, when the dose of the UV therapy was decreased, the patient showed signs of recurrence. Researchers want to monitor the patient for two years to see if the purpuric eruptions will stop and they believe that this patient will have promising results.

"Successful treatment of generalized childhood Schamberg's disease with narrowband ultraviolet B therapy."

This research article demonstrated two cases where two children had purpuric rashes. The children were placed on UVB therapy and were monitored weekly for purpuric eruptions. One of the child received 10 treatments of UVB therapy, while the other child received 20 treatments. The child that received the 20 treatments did not show signs of purpuric eruptions and the skin lesions disappeared. However, the child that received the 10 treatments, showed signs of recurrence. Most of the rash disappeared, but some of it reappeared on the body. Researchers believe that the narrowband UVB therapy used on children has proven to remove and control the skin lesions.

A single case report suggested that oral dapsone may be useful for prevention. However, the efficacy of oral dapsone as prevention has not been demonstrated very clearly until now.

NEH is self-limited and usually resolves without treatment. In the overwhelming majority of the cases, spontaneous resolution occurs within 1–2 weeks.

However, if the patient developed NEH after chemotherapy, the offending cytotoxic drug has to be discontinued, and the patient must avoid this particular cytotoxic drug in the future, because NEH usually re occurs upon re exposure to the same cytotoxic drug.

Despite the fact that NEH is self limited and usually resolves without treatment, some researchers use treatment, mainly systemic corticosteroids, although the efficacy of such a therapy has not been demonstrated in a large randomised controlled clinical trial until now.

At certain times of the year this can be a problem in some areas of the Bahamas particularly around New Providence.

This infection affects multiple organs, including the eyes, brain, lung, and liver, and can be fatal.

Urticarial allergic eruption is a cutaneous condition characterized by annular or gyrate urticarial plaques that persist for greater than 24 hours.

Systemic corticosteroids such as (prednisone) can produce rapid improvement and are the “gold standard” for treatment. The temperature, white blood cell count, and eruption improve within 72 hours. The skin lesions clear within 3 to 9 days. Abnormal laboratory values rapidly return to normal. There are, however, frequent recurrences. Corticosteroids are tapered within 2 to 6 weeks to zero.

Resolution of the eruption is occasionally followed by milia and scarring. The disease clears spontaneously in some patients. Topical and/or intralesional corticosteroids may be effective as either monotherapy or adjuvant therapy.

Oral potassium iodide or colchicine may induce rapid resolution.

Patients who have a potential systemic infection or in whom corticosteroids are contraindicated can use these agents as a first-line therapy.

In one study, indomethacin, 150 mg per day, was given for the first week, and 100 mg per day was given for 2 additional weeks. Seventeen of 18 patients had a good initial response; fever and arthralgias were markedly attenuated within 48 hours, and eruptions cleared between 7 and 14 days.

Patients whose cutaneous lesions continued to develop were successfully treated with prednisone (1 mg/kg per day). No patient had a relapse after discontinuation of indomethacin.

Other alternatives to corticosteroid treatment include dapsone, doxycycline, clofazimine, and cyclosporine. All of these drugs influence migration and other functions of neutrophils.