Summer Bites, Stings, Hives, and Rashes

Contemporary ClinicAugust 2016
Volume 2
Issue 4

For many of our patients, the season means walks in the park, evenings by the shore, backyard barbecues, and outdoor sports.

For many of our patients, the season means walks in the park, evenings by the shore, backyard barbecues, and outdoor sports. However, with the warm days and beautiful evenings comes the increased incidence of insect bites, stings, and skin rashes. Because of their commonality, retail clinicians are sure to encounter patients with these skin ailments before the next change of season. Optimizing health outcomes for patients depends on clinicians teaching the keys of self-care and helping them set their expectations for symptom resolution appropriately. This article reviews common summer bites, stings, hives, and rashes, and also provides counseling points to share with patients.


Insect bites are more than just a bothersome part of summer; on rare occasions, they may lead to more serious conditions, such as Lyme disease (caused by a tick bite) or the West Nile or Zika virus (caused by mosquito bites). Insect bites are puncture wounds or lacerations made by insects such as mosquitos, ticks, gnats, fleas, horseflies, bed bugs, and spiders. An insect may bite when it is agitated and defends itself or when it wants to feed. An insect releases its saliva when it bites the skin, triggering erythema, inflammation, pain, and pruritus at the puncture site. The bites can range in size from a very small papule to a massive welt.

Patients will have varying degrees of reactivity at the site of the bite, depending on skin type and known sensitivities. Bite marks may become infected because of excoriation and rubbing, and they may exhibit signs of infection, such as pus inside or around the bite, swollen glands, fever, and/or flu-like symptoms. Typically, bite marks do not last more than a few hours. However, some patients may have a hyper reaction when the same type of insect bites them for a second time. Once this occurs, the patient becomes sensitized to the insect’s saliva, and a pruritic wheal or papule may develop and last for several days. Because there is no correlation between the size or appearance of the bite mark and the type of biting insect, patient history is critical to diagnosis.

In the majority of cases, reactions to insect bites are mild, local, and straight forward to treat. Patients may find that placing a cold compress over the bite area, applying a topical corticosteroid or anesthetic cream, or taking a non-steroidal anti-inflammatory drug or paracetamol (eg, acetaminophen) may help. In more severe cases, or when the bites are near the eyes, a short course of oral corticosteroids may be needed. Patients should be advised that if an insect bite is uncommonly pruritic, acutely swollen, painful, warm to the touch, or presents with an unusual rash or systemic symptoms (eg, fever, vomiting, nausea, or musculoskeletal complaints), then further evaluation and testing is warranted.

There are 2 major reasons why an insect will bite a particular person: (1) the presence of carbon dioxide production, and (2) the lipid mix on the surface of the skin. For example, mosquitos find humans by determining where carbon dioxide is being produced. Although humans manufacturing carbon dioxide is a given, each individual’s lipid mixture varies and is made up of cholesterol, triglycerides, ceramides, and other fats. Certain lipid mixtures are more appealing to insects than others, which explains why some patients report feeling that they are often a “target” for insect bites.

Since a patient’s skin lipid mix is based on genetics, and knowing that an individual cannot change his or her DNA, the CDC recommends that adults use bug repellents that contain diethyltoluamide (DEET), picaridin, or oil of lemon eucalyptus. Insect repellents containing DEET should not be used on children younger than 2 months, while oil of lemon eucalyptus products should not be used on chil dren younger than 3 years.


When an insect stings an individual and injects its venom into the skin, that patient’s reaction at the site is painful, erythematous, inflamed, and pruritic. However, some patients are allergic to the venom, and these symptoms progress to anaphylaxis in quick order. It is normal for a bee, hornet, yellow jacket, fire ant, or wasp sting to cause a minor rash and localized swelling; however, a more serious systemic reaction leading to anaphylaxis presents with widespread pruritus, urticaria, shortness of breath, swelling of the tongue/throat,nausea, vomiting, or diarrhea.

For mild to moderate reactions, treatment involves removing the stinger as soon as possible, washing the area with soap and water, and applying cold compresses or ice. When removing the insect stinger, a quick scrape with a fingernail is often sufficient. It is important not to pinch the sting or use tweezers, as this can inject more venom into the site. Patients may find relief by applying topical creams (eg, hydrocortisone, aloe, antihistamine) to the affected area.

For anaphylactic reactions, prompt emergency treatment with epinephrine is required. When the patients report experiencing anaphylaxis from an insect sting without prior history of a venom allergy, they should be referred to an allergist for further evaluation. An allergist will perform allergen skin testing as a part of the assessment. Patients who demonstrate sensitivity (positive results) to the skin tests and receive a diagnosis of venom allergy will be considered as candidates for allergy immunotherapy injections. There is no sublingual alternative when desensitizing a patient with a venom allergy.

Patients with a history of venom allergy who have been evaluated by an allergist will know to always carry a 2-pack epinephrine injector set with them and have a plan for emergency action in place. If the epinephrine injector is used, the patient should call 9-1-1, contact his or her health care provider, or go to the nearest emergency department for evaluation of a possible biphasic reaction. A biphasic reaction is a second episode or wave of anaphylaxis, and it occurs without additional exposure to the allergen. It is estimated that biphasic reactions happen in up to 20% of anaphylaxis cases.

Patients should know that if stinging insects are close by, they should remain calm and move slowly away. Because these insects are drawn to brightly colored clothing and perfume, it is best to avoid those when outdoors for a long period of time. The smell of food attracts insects, so awareness is necessary when cooking, eating, or drinking sweet drinks like soda or juice (particularly when drinking from straws or cans, which are common places for stinging insects to hide). At-risk patients should wear closed-toe shoes outdoors, avoid going barefoot, and avoid loose-fitting garments that can trap insects between material and skin.


Urticaria, also known as hives, is a rash with pale red, raised, and pruritic lesions that can appear anywhere on the body and may change shape, location, and vary in intensity over short periods of time. Urticaria is common year round, but in some patients, the summer season makes everything worse. Rising body tempratures in the summer months, whether caused by direct sunlight or increased outdoor activity, increase blood flow to the skin and provoke mast cells (within the dermis) to release histamine, thereby causing an urticarial exacerbation. Regardless of the cause of the urticaria, the summer season may cause a flare of symptoms.

Urticaria often appears suddenly and dissipates just as rapidly. For diagnostic purposes, applying pressure to the center of the hive should make it instantaneously turn white, a process called blanching.

Mild urticaria often disappears spontaneously after a few hours, while a moderate case necessitates first-line treatment with an oral antihistamine and will last days to weeks, or beyond. Patients often prefer the non-sedating, second-generation antihistamines to the sedating first-generation antihistamines for first-line treatment. When needed, subsequent first-line therapy may include the addition of histamine blockers. If the hives encompass the face, approach the eyes, or are acutely pruritic, adding an oral corticosteroid may be necessary. Patients should see a health care provider for further evaluation if hives last more than 3 to 4 days. If patients additionally develop angioedema or anaphylaxis, they should be advised to seek medical attention immediately.

When heat is a known aggravator, patients should try to avoid being outdoors on warm days for a long period of time. Patients should have a complete allergy work-up to properly diagnose their urticaria and learn how to manage avoidance of their triggers.


The high rainfall, humidity, and temperatures of the summer season, combined with the increased carbon dioxide levels of the past few years, promise to yield a potent crop of ivy-related plants this year. Hiking, camping, and playing outdoors are perfect summer activities; however, developing a rash from poison ivy, oak, or sumac while doing so can interrupt your patient’s day.

Poison ivy, oak, and sumac rashes are a form of allergic contact dermatitis and are caused by oils found in the leaves, stems, and roots of the plants called urushiol. Poison ivy is the most recognized form of the 3 plants and is similar in appearance to poison oak and sumac. The rash is erythematous and very pruritic, involving inflammation and blistering. According to the American Dermatology Association, 85% of individuals develop a rash when they get urushiol on their skin. The rash often does not start until 12 to 72 hours after the patient comes into contact with the oil. For most, the rash resolves within a few weeks.

The initial treatment for poison ivy, oak, or sumac is to use a cold compress, calamine lotion, hydrocortisone cream, or antihistamine to relieve itching. However, if the rash is more severe or encompasses the face (specifically the eye), a short burst of oral corticosteroids may be necessary. Inflammation is a sign of a serious reaction and necessitates an immediate evaluation by a health care provider. If the patient is having respiratory or swallowing difficulties, they should call 9-1-1 or go to an emergency department immediately.

It is often comforting for patients to know that the rash is not contagious and only spreads when the oil touches other parts of the body. It is not possible to get this rash from merely touching someone who has the rash, as the skin absorbs the oil too quickly. It is also not possible to get this rash from touching the fluid in the blisters of the rash. An individual must come into contact with the plant oil to develop the rash. Interestingly, dogs and other animals do not develop this type of rash, yet if the plant oil is on their fur, it is feasible for patients to develop the rash after touching the animal.

It is important to share with patients that the only way to prevent plant-induced contact rashes is to be hypervigilant of their surroundings when outdoors. Patients should be familiar with the appearance of their rash-provoking plant and avoid walking through tall grasses when possible. A simple reminder to share with patients is: “Leaves of 3, let them be.”


Summer often presents the perfect scenario for the development or exacerbation of all that itches. The increased number of insects and plants in the environment, along with longer, hotter days and spending more time outdoors, contributes to an increase in incidents of rashes, hives, bites, and stings during this season. Most of these skin ailments are self-limiting and will resolve spontaneously after a few hours or days. However, those with severe symptoms may require further evaluation, referral to an allergist, or emergency treatment. Regardless, retail clinicians are in a prime position to educate their patients on the primary prevention and avoidance measures of summer rashes,hives, bites, and stings

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