Two common types of conjunctivitis are bacterial conjunctivitis and allergic conjunctivitis. In this regard, one of the key symptoms that differentiate the allergic form from bacterial is whether itching is present. If there is no itching, it is unlikely to be allergic conjunctivitis (Granet, 2008). Another differentiation between allergic and bacterial forms is whether the patient initially presents with symptoms in both eyes or only one. Allergic conjunctivitis presents most often in both eyes, since it is rare for only one eye to be exposed to the allergen; bacterial (and viral) forms are more likely to begin in only one eye initially, though the infection may spread soon afterwards (Granet, 2008). Thus, symptoms of allergic conjunctivitis include watery, itchy, red, sore, swollen, and stinging eyes, and photophobia (Palmares et al, 2010). Symptoms of bacterial conjunctivitis include abrupt onset, eye irritation, conjunctival redness with a yellow-green discharge that seems worse in the mornings (Granet, 2008; Hovding, 2008). Usually the bacterial form does not present with pain or impaired vision (Sethuraman & Kamat, 2009).

Treatment for bacterial conjunctivitis may not be necessary since these infections are usually self-limiting (Sethuraman & Kamat, 2009). However, a broad-spectrum antibiotic such as polymyxin B sulfate and trimethoprim sulfate, gentamicin, erythromycin, or tobramycin, used as drops or ointments, may both shorten the duration and help prevent the spread to other people (Sethuraman & Kamat, 2009). For allergic conjunctivitis, steroid nasal sprays and antihistamine pills may help, along with using eye drops to relieve the itchy, watery eye symptoms (Patient information—allergic conjunctivitis, 2011). Immediate referral to an ophthalmologist is indicated if there is severe pain, loss of vision, pain or loss of vision with contact lenses, trauma, recent eye surgery, or chemical injury (Noble & Lloyd, 2011).

For those with allergic conjunctivitis, common allergens that can stimulate the condition include smoke, chemicals, dust, wind, cold dry air, and UV light (either from the sun or tanning devices) (Peate, 2009). Patients should be instructed to avoid these irritants as much as possible to help relieve symptoms. In addition, it is not a good idea for any patient with conjunctivitis (whether bacterial or allergic) to use contact lenses until the condition clears up. Frequent cleaning of the eyes with cotton balls soaked in cool water is encouraged, but it is important to wash hands both before and after doing this. Also, the patient should avoid rubbing his or her eyes until the condition clears up (Peate, 2009).