Bumps on the Backs of the Legs

At some point in your life, you may have developed bumps or lumps on the skin on your legs. There are many reasons for skin conditions to arise and often the cause is not obvious. Allergies, irritants, your genetic makeup and certain diseases and immune system problems can cause dermatitis, hives and other skin conditions.

Symptoms

You should monitor the condition of any skin bumps to help your doctor diagnose the cause. Revealing characteristics include color, size, shape and the presence of other symptoms or signs. A lump under the top layer of skin, showing mobility when you roll it with your fingers, may be the result of an injury, a sebaceous cyst or tumor. Red itchy bumps and skin rash may indicate an allergy, insect bites or the result of a clogged hair follicle. Red to purple bumps, accompanied by aching joints and fever, could indicate an infection or virus, according to Family Doctor.org. Your doctor may need to do a skin biopsy to assess your skin condition.

Types

A common cause of skin bumps on the back of legs is contact or atopic dermatitis, which is often triggered by sensitivities to substances such as cosmetics, soap, chemicals or even from rubber in boots. Certain medications and drugs can cause some forms of dermatitis. Stasis dermatitis results from varicose veins, according to the Merck Online Manuals. Skin infections include bacterial, fuhgal or viral infections such as shingles, which can lie dormant for years and emerge as red spots and bumps. Henoch-Schonlein purpura is an infection of red to purple bumps on the lower legs, sometimes accompanied by aching joints and fever, according to Medline Plus. Another cause of skin bumps are parasites such as chiggers, the larva of mites, which present as itchy red bumps from feet and ankles upward, according to the Missouri Department of Conservation.

Unique Conditions

Some skin conditions develop only under unique circumstances such as pregnancy. Pruritic urticarial papules occur late in pregnancy as small, red bumps often starting on the abdomen and spreading to the thighs. Itchy large patches generally disappear after giving birth. Another skin condition associated with pregnancy is prurigo. Itchy, tiny bumps, similar in appearance to insect bites, appear anywhere on the skin. Prurigo can continue for several months after the baby is born, according to the American Congress of Obstetricians and Gynecologists.

When to Call the Doctor

Some skin bumps can be a symptom of a serious disease such as sarcoidosis, which can affect the lungs or lymph nodes. Sarcoidosis, most common in women, causes a rash of red or reddish-purple bumps to appear on ankles and shins, according to the National Heart, Lung and Blood Institute. Seek medical care if your skin condition worsens, if red streaks appear near an infected area, if a fever develops or if other family members experience similar symptoms.

Treatments

Most skin conditions can be treated with over-the-counter or prescription medications such as anti-itch creams, topical cortisone and fungicides. Oral antihistamines may control the symptoms of hives, rashes or allergy-related skin conditions. More severe conditions may require corticosteroids such as prednisone, antidepressants and epinephrine, according to Mayo Clinic. Bumps that leave lasting scars may require cosmetic treatments such as laser therapy.