A rash here and an itch there may seem minor — and usually they are. Yet sometimes symptoms that appear to be “only skin deep” actually are warning signs of serious health problems.

This is one reason why it is important to get regular skin checkups, typically yearly. Of course your dermatologist looks for skin cancer, including the potentially deadly malignant melanoma…but during a full-body exam, the doctor may spot subtle signs indicating a problem inside the body.

Below are symptoms that your dermatologist should look for during a checkup — and that you should report promptly if you notice them first. Your dermatologist may treat the problem if he/she feels that it is primarily a skin disorder…or, if an underlying condition is suspected, you may be sent to a specialist or back to your primary care doctor for a full diagnosis and treatment.

Referrals to a dermatologist: The American Academy of Dermatology, 888-462-3376, www.aad.org.

RED NOSE AND CHEEKS

Skin problem: Often the cause is rosacea, a chronic inflammatory skin disorder sometimes characterized just by facial redness…and sometimes by small red bumps on the face. Though it cannot be cured, rosacea is not dangerous. Usually it can be controlled with topical and/or oral antibiotics.

Below-the-skin problem: Systemic lupus erythematosus sometimes causes a butterfly-shaped red rash that goes across the bridge of the nose and onto the cheeks. Lupus is a chronic auto­immune disorder that affects nine times as many women as men. The rash does not respond to acne drugs and may be exacerbated by certain antibiotics, such as sulfa drugs or tetracycline. Untreated, lupus can damage the joints, kidneys, heart, lungs, digestive tract and nervous system.

Action: If lupus is suspected, a rheumatologist orders diagnostic blood and urine tests. There is no cure, but prompt treatment with medication (such as steroids) and lifestyle changes (including avoiding alcohol and excessive sunlight) minimizes symptoms and reduces risk for complications.

BREAST RASH

Skin problem: A patch of itchy, bumpy redness on the breast could be atopic dermatitis (also called eczema), an inflammatory skin condition common in allergic individuals. Atopic dermatitis frequently affects other areas, too — especially the crooks of the elbows and the backs of the knees. Symptoms often can be controlled with topical medication, such as steroid cream.

Below-the-skin problems: If a scaly rash appears on or around the nipple, it may be Paget’s disease of the breast, a rash that can signify underlying breast cancer or intraductal carcinoma (abnormal cells in the breast duct that may become invasive cancer). If the breast is swollen and warm and its skin is discolored or pitted (like an orange peel), this may signal inflammatory breast cancer, most often diagnosed in women in their 50s. A breast rash caused by cancer may not respond to topical creams, though sometimes symptoms spontaneously abate briefly.

Action: A biopsy is needed to confirm the diagnosis. An oncologist provides guidance on treatment options, including surgery, radiation and/or chemotherapy.

UNDER-EYE CIRCLES

Skin problems: Dark circles worsen with age as skin thins and loses elasticity, making veins more visible. Excess sun darkens the area further by increasing production of the skin pigment melanin. Recommended: Daily use of sunscreen helps prevent sun-related changes.

Below-the-skin problem: Darkening of the skin around the eyes could be “atopic shiners,” which sometimes occur in people who have allergies. One theory suggests that atopic shiners result from chronic rubbing of itchy skin in the eye area. Additional allergy-related skin symptoms include rough, dry skin…cracked skin on the hands and feet…and tiny, hard red or white bumps called keratosis pilaris on the upper arms, thighs, buttocks and face.

Action: An allergist can perform skin tests to determine what you are allergic to and then recommend avoidance strategies, medication and/or immunotherapy injections to minimize allergic symptoms, such as asthma or hay fever.

But: Often the skin signs of allergy, such as atopic shiners, persist even when other symptoms respond to treatment.

ITCHING

Skin problem: Common causes include dry skin, sunburn, allergic reactions, insect bites, scabies infestation, poison ivy, bacterial or fungal infections, psoriasis or stress. Treatment depends on the specific condition. For quick temporary relief, it helps to run cool water or place a cold compress on the area…soak in an oatmeal bath…use an over-the-counter cream with camphor, menthol, calamine, benzocaine, hydrocortisone or triamcinolone…and/or take an oral antihistamine.

Below-the-skin problems: Persistent itchiness could signal any of the following…

Hodgkin’s lymphoma. Intractable itchiness that does not respond to treatment can be an early sign of this cancer, which starts in the cells of the immune system. Other symptoms include swollen lymph nodes, cough, fever, night sweats, fatigue and/or unintended weight loss.

Action: An oncologist confirms the diagnosis with blood tests, imaging tests and lymph node biopsy. Treatment generally includes chemotherapy and radiation.

Liver disease. A number of liver problems — including a viral disease, such as hepatitis, or the metastasis (spread) of cancer to the liver — can produce intense itching.

Action: A gastroenterologist does tests, such as blood work, imaging studies and/or biopsy, to determine the exact nature of the problem. Treatment depends on the specific diagnosis.

Thyroid disorder. Thyroid hormones regulate metabolism. Both hyperthyroidism (overactive thyroid gland) and hypothyroidism (underactive thyroid) can produce generalized itching. Other symptoms of hyperthyroidism include a rash and swelling on the shins, sudden weight loss despite an increased appetite, rapid or irregular heartbeat, hand tremors, fatigue and/or increased sensitivity to heat. Untreated hyperthyroidism can cause severe heart problems and osteoporosis. Hypothyroidism often is accompanied by dry skin, weight gain, muscle aches and fatigue. Untreated hypothyroidism may lead to infertility and heart disease.

Action: An endocrinologist orders blood tests to measure hormone levels. With medication to regulate thyroid hormones and sometimes with surgery, symptoms generally subside and complications are prevented.