Skin Diseases Of The Scalp

There are number of scalp diseases and conditions, which range from mild to extremely serious.

Inflammatory Diseases of the Scalp  

Seborrhoeic Dermatitis (Dandruff) 

The cause of seborrhoeic dermatitis is unknown. There are two types of seborrhoeic dermatitis: infantile seborrhoeic dermatitis, commonly seen in newborns and babies, and adult seborrhoeic dermatitis, commonly seen in middle-aged adults.

Seborrhoeic dermatitis appears as yellowish, greasy scales on the scalp. The underlying skin is red. If mild, only patchy areas of the scalp are affected, but in more severe cases, there may be diffuse scaliness and redness. Seborrhoeic dermatitis may affect the skin over the eyebrows, inner cheeks, chest, back and groin. The condition may or may not be itchy. It is not a fungal infection although yeast infections have been reported to be associated with it. Patients with HIV infection may develop very severe seborrhoeic dermatitis.

Treatment of seborrhoeic dermatitis consists of mild antiseptic or antifungal shampoos and mild topical steroid lotion or gel. The condition tends recur.


Psoriasis of the Scalp 

Psoriasis is an inflammatory skin disease characterised by an increased rate of skin cell turnover. It appears as plaques with thick scales on the skin and scalp. The skin lesions appear as discrete scaly plaques on the scalp and along the hairline, and often extend to the forehead and sides of the scalp. The plaques are pink and covered by silvery scales. Psoriasis may also result in changes to the nails. The condition is usually non-itchy. 

Psoriasis of the scalp is treated with coal-tar shampoo and coal-tar ointment or a topical steroid spray or gel.

Contact Dermatitis and Skin Allergies 

Contact dermatitis  is an inflammatory condition caused by an external agent. Irritant contact dermatitis of the scalp can occur from overuse of medicated shampoo, chemicals such as bleaching or perm lotion, or excessive heat applied to the scalp. Many topical preparations for hair and scalp can cause skin allergies, the most common being hair-dye allergy. Other possible allergens are fragrance in hair lotion, chemical in perm lotion and medicaments/preservatives in shampoos and hair/scalp lotion.

Dermatitis presents as itchy, scaly, red patches on the scalp, hairline and ears. In the acute phase, there may be cysts, and swelling can occur, which may extend to the eyelids.

If you have symptoms of contact dermatitis, you should consult your doctor for treatment and investigations to determine the cause. Preventive measures can be taken to prevent a relapse. A patch test to ascertain the cause of allergy may be necessary.

Lichen Planus  

Lichen planus is an inflammatory disorder of the skin which can cause bald scarring patches on the scalp. The cause is unknown. 

It starts as a reddish-purplish patch or plaque on the scalp and may enlarge with loss of hair. Afterwards, the affected skin is scarred and bald. The skin is often itchy and may also infect the inside of the mouth and the nails. 

On other parts of the body, lichen planus appears as bluish, itchy, scaly patches. Lichen planus usually clears spontaneously after a few years.

To prevent scarring and permanent balding, lichen planus of the scalp should be treated early with topical steroids or intralesional injections of steroids on the affected skin.

Discoid Lupus Erythematosus (DLE) 

This is an autoimmune disease affecting predominantly the skin and appears as bald, scaly red patches on the scalp. The skin thins and prominent capillaries can be seen in the patches. Hair loss in these scarred patches is obvious and often permanent. The condition is painless and not itchy. Other areas of the skin, e.g. the face and ears, are often also affected. Such skin lesions are often sun-sensitive. Laboratory tests including a skin biopsy are required to confirm the diagnosis.

DLE should be treated immediately to prevent progressive scarring and balding. There are effective treatments for the disease but scarred lesions are usually not responsive to treatment. Occasionally, internal organs such as the lungs, kidneys and heart may be affected, leading to a condition called systemic lupus erythematosus. As such, sufferers should have regular check-ups with their doctor.

Alopecia Areata 

This is an autoimmune disease of the skin, which often affects the scalp, causing one or more bald patches. It is often not preceded by redness or itching. Bunches of hair just fall out suddenly over a few days leaving behind completely bald patches. The underlying skin appears normal. The cause of alopecia areata is unknown. Most patients recover spontaneously after several months. In severe cases, the whole scalp may be affected, leading to complete baldness. On rare occasions, the disease may be associated with other skin disease such as thyroid disease.

Treatment consists of intralesional steroid injections or regularly painting the affected skin with chemicals. You should consult your doctor for early treatment. 

Tumours and Birthmarks on the Scalp

Naevus Sebaceous 

Naevus sebaceous are birthmarks originating from the skin’s oil glands. They are present at birth, initially as a faint yellowish patch that becomes raised, rough and wart-like as the child grows older. The lesion usually appears on the scalp, but can occasionally occur on the face and neck. The lesion is asymptomatic. It often enlarges at puberty, and there is a very small risk of cancer developing on the birthmarks during adulthood. They can be removed surgically.

Seborrhoeic Keratoses (Seborrhoeic Warts, Age Spots) 

These are benign growths on the scalp or other parts of the body. They appear as discrete, sharply demarcated brownish to black patches or raised flat-topped lumps of various sizes, and can have either a smooth or rough surface. They usually occur in older adults and are very common in people over 50. The lesions often appear on the face, but some may occur on the scalp. 

These harmless lesions are not associated with any symptoms and do not need treatment, but can be destroyed and removed by liquid nitrogen applications, electrosurgery, shave excision or laser surgery for cosmetic reasons. Learn more about skin cosmetic surgery options here

Solar Keratoses 

Solar keratoses are pre-cancerous skin lesions on sun-exposed skin of the face and scalp. On the scalp they occur on balding individuals who have had long exposure to the sun. They are often seen in fair-skinned people and in middle-aged and older people. Solar keratoses appear as ill-defined red scaly patches on the skin. The surface of the lesion looks and feels rough, like fine sandpaper. The lesion is painless and does not itch. If left untreated solar keratosis may develop into skin cancer.

Solar keratoses must be destroyed to stop cancerous transformation. It is usually destroyed with liquid nitrogen applications or topical anticancer cream e.g. 5-fluorouracil. Patients with solar keratoses must avoid further exposure to the sun and use sunscreen cream daily. New lesions should be treated when they occur. A skin biopsy may be necessary to ascertain if a cancer has developed.

Angiosarcoma 

This is a rare blood vessel cancer of the skin. It tends to appear on the scalp, face and ears. It usually occurs in elderly patients, and commonly appears as single or grouped bluish-red nodules or plaques on the scalp, face or ears. The lesions may occasionally be mildly tender but are often painless. Early diagnosis is essential. A skin biopsy is needed to confirm the diagnosis.

Patients with angiosarcoma are referred to an oncologist for treatment. Localised lesions can be removed by surgery, but large lesions need radiotherapy. The prognosis of angiosarcoma is generally poor.

Infections on the Scalp 

Fungal Infection (Ringworm, Tinea Capitis) 

Ringworm infection of the scalp is caused by a fungal infection and is more common in children than in adults. It appears in a variety of ways, depending on its severity and source of infection. In mild cases, the fungal infection appears as itchy, scaly patches on the scalp. The hair follicles and hair are infected and the infected hairs break and fall out, leaving bald patches. The underlying skin may be red and inflamed. In severe infection (often from infected pets), the scalp skin becomes very red, tender and boggy. Pus may exude from the inflamed skin and boils/abscesses (called kerion) may form. Infected hair falls out and crusting may occur.

Fungal infections of the scalp can be effectively treated with oral antifungal drugs and good hair care. The source of infection, e.g. pets, should be treated simultaneously to prevent recurrence. Early recognition and treatment of the fungal infection will prevent permanent scaring and balding. Consult your doctor immediately if you suspect you have fungal infection of the scalp.

Bacterial Infections of the Hair Follicles (Folliculitis, Boils) 

Bacterial infection of the hair follicles causes scalp folliculitis, or inflammation of the hair follicles/pores. Scalp folliculitis appears as pimple-like eruptions on the scalp. The small, discrete red lumps are tender and are often scattered on different areas of the scalp and pustules may develop. Some people are more susceptible to such infection than others. If the infection becomes too frequent, tests should be carried out to ascertain if there is any abnormality in the immune system.

Folliculitis can be effectively treated with appropriate oral antibiotics. Good hygiene, regular washing of the scalp and hair with mild antiseptic shampoo will help prevent recurrences. Occasionally, long-term oral antibiotics may be necessary to suppress infections.

Shingles (Herpes Zoster) 

Shingles is caused by the virus that also causes chickenpox. Patients with shingles have always had chickenpox in the past as shingles represents a reactivation of the chickenpox virus. It is often seen in people with reduced immunity e.g. following a viral infection, cancer, etc. 

The skin eruptions appear in a linear pattern following the distribution of a branch of the nerve. There is often preceding pain and itch just before the appearance of skin eruptions. A very painful blistering rash is followed shortly afterwards by erosions and crusting over affected areas of the skin e.g. on the forehead and anterior scalp, or the neck and back of the scalp. The condition is self-limiting and should clear after about two weeks. However, severe pain may persist for months after the skin lesions have cleared. 

The elderly are at a higher risk of developing post-herpetic neuralgia. Patients with shingles should see their doctor and may require investigation for any underlying cause of lowered immunity.

Shingles can be effectively treated if appropriate antiviral drugs are taken very early (within 48 hours of the appearance of the symptoms). Oral antiviral drugs can reduce the duration and severity of shingles. Consult your doctor immediately if you suspect you have shingles.
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