Skin conditions, particularly those that affect the scalp and lead to alopecia, can have a serious impact on a patient's quality of life.
In some cases of alopecia accurate diagnosis can lead to treatment and hair regrowth. For other patients the resultant scarring may prevent hair regrowth and the alopecia may be permanent. Coming to terms with this can be difficult, especially for women, and support from the medical profession may be helpful.
1 Scalp Psoriasis
Scalp psoriasis affects 2-3% of the UK population. It
presents as red, inflamed skin with a surface scale, which
may be associated with alopecia. Around 50% of patients with
plaque psoriasis will also have scalp involvement, but scalp
psoriasis may occur as a single entity.
Scalp psoriasis is often confused with seborrhoeic dermatitis, but on closer inspection the scale is fine and silvery-white, whereas with seborrhoeic dermatitis it is more yellow and greasy.
Treatment can often be a challenge, and will need commitment by the patient to comply with messy regimens of ointments and lotions.
2 Seborrhoeic Dermatitis
Seborrhoeic dermatitis is a common papulosquamous condition
that affects sebum-rich areas of the body, such as the scalp,
face, trunk, axillae and groin.
On the scalp the condition varies in severity, from mild dandruff to an exfoliative erythroderma. In severe cases an underlying condition may be present, such as HIV. Parkinson's disease also seems to worsen the condition.
Although Malassezia organisms are not causative, they seem to be a cofactor.1 They are linked to T cell depression, increased sebum levels and activation of the alternative complement pathway.
If symptoms suggestive of seborrhoeic dermatitis occur in childhood, the cause is far more likely to be tinea capitis. This should be excluded before a diagnosis of seborrhoeic dermatitis is made in patients under the age of 15.
Treatment once a week with an antifungal shampoo, such as ketoconazole, as well as daily treatment with a tar-based shampoo, is usually enough to keep the condition under control.
3 Tinea Capitis
Tinea capitis is a fungal infection of the scalp. It varies
in presentation, from mildly scaly, non-inflamed dermatoses
similar in appearance to seborrhoeic dermatitis, to more
inflamed dermatoses that cause alopecia. If untreated these
can progress to a very inflamed abscess, called a kerion,
which may result in scarring and permanent loss of hair.
The causative agent is usually Trichophyton spp. or Microsporum spp. fungi.
Tinea capitis is most common in children, with peak incidence between three and seven years of age. However, adults can also be affected, as in this case.
Diagnosis is made by examination and culture of skin or hairs plucked from the affected areas. Infected hairs appearing as broken stubs are best.
Treatment depends on the causative organism and the degree of inflammation. Griseofulvin was the first effective oral treatment, and newer agents include itraconazole and terbinafine.2
4 Alopecia Areata
Alopecia areata is a recurrent, non-scarring hair loss that
can affect any hair-bearing area of the body. It affects up
to 0.15% of the UK population3 and accounts for 2%
of dermatology outpatient appointments in the UK.3
It can occur at any age, but 60% of those affected develop
their first patch before the age of 20, and the peak
incidence is from 15 to 29 years of age.4
Men and women are affected equally and no racial variation has been noted.3
Although the aetiology is not certain, alopecia areata is most likely to be a T cell mediated autoimmune condition, affecting genetically predisposed individuals.
A precipitating event can be determined in around 15% of cases. Such events include:
• Major life events (divorce, bereavement, shock)
• Febrile illness
• Drugs
• Pregnancy
• Trauma.
Alopecia areata is asymptomatic in the majority of cases. However, around 14% of patients will describe a burning sensation over the affected area.
Although it is a benign condition, the psychological impact must always be considered.
5 Alopecia Mucinosa
Alopecia mucinosa, also known as follicular mucinosis, was
first reported in 1957.5 The areas affected
consist of follicular papules and indurated plaques, which
cause damage to the hair follicles, leading to hair loss. The
accumulation of mucinous material in the damaged follicles
and sebaceous glands causes inflammation and subsequent
degenerative changes.
Although any area of the body may be affected, the most commonly affected areas are the scalp, head and neck.
Unlike alopecia areata, this is a rare condition. Correct diagnosis is important because 15-40% of those affected will go on to develop a lymphoma, and a percentage of these patients will already have a lymphoma at the time of diagnosis.
A punch biopsy of the affected areas with histological examination will allow differentiation from other forms of alopecia. Histologically there is follicular degeneration and deposition of mucin within the hair follicles.
6 Pseudopelade of Brocq
Pseudopelade of Brocq is not a specific disease, but
describes end-stage scarring alopecia where a cause has not
been found; it is a diagnosis of exclusion.
The term comes from the French 'pelade', which means alopecia, and was first described by Brocq.6 The same pattern of hair loss occurs in the end stages of discoid lupus erythematosus and lichen planopilaris.
Pseudopelade of Brocq is an uncommon condition that usually only affects adults, although cases have been reported in children. Lesions tend to be randomly distributed, irregularly shaped and occur in clusters on the scalp. Biopsy can be useful to exclude other forms of scarring alopecia.
7 Discoid Lupus Erythematosus
Discoid lupus erythematosus is a chronic scarring atrophy producing a photosensitive dermatosis. It can occur at any age, but is most common in patients aged 20 to 40 years.
The disease usually manifests after UV exposure. Patients probably have a genetic predisposition; however, the precise genetic factors that increase the risk of developing the condition are unknown.
Lesions characteristically start as an erythematous plaque or papule with scaling. This progresses to a thickened area in which pigmentary changes may occur, with central hypopigmentation and a hyperpigmented border. As lesions spread outward they may merge, and follicular plugging can occur. Resolution of these active areas may leave scarring and atrophy.
8 Lichen Planopilaris
Lichen planopilaris is also called follicular lichen planus. It initially appears as small red papules around the base of the hair, which progress to a scarring alopecia. This may cause widespread permanent hair loss, as in this case.
As with other forms of lichen planus, the nails and buccal mucosa may also be affected.
Diagnosis can be confirmed by punch biopsy, which will reveal a lichenoid tissue reaction within the epidermis. A recent paper has reported the successful treatment of this condition with mycophenolate mofetil, an immunosuppressive drug.7
9 Lentigo Maligna
Lentigo maligna, also referred to as Hutchinson's freckle, was originally thought to be an infection because of its slow growth. The term is now used to describe lesions that are confined to the epidermis; those that extend into the dermis are termed lentigo maligna melanoma.
Unlike nodular and superficial melanomas, which affect a younger age group, lentigo maligna presents in patients with a mean age of 65 years. Peak incidence is in the seventh and eighth decades of life. Interestingly, those affected by lentigo maligna melanoma have higher occupational sun exposure and lower recreational sun exposure than patients with other forms of melanoma.8
10 Actinic Keratosis
Actinic keratosis is a sun-induced skin condition that commonly affects the scalp of balding men. It presents as an area of hyperkeratosis and, if left untreated, may progress to squamous cell carcinoma.
Treatment options include cryotherapy or topical NSAID gels, such as diclofenac. If there is any diagnostic doubt a biopsy should be taken, or the lesion should be curetted and the base cauterised.
The other important part of management is to educate patients about the importance of protecting their skin from further sun exposure. Patients should be advised that the best way to do this is to wear a wide-brimmed hat.
11 Fleshy Papilloma
Benign raised naevi are quite common on the scalp. Although not a cosmetic problem because of overlying hair, they are often caught by combs and brushes or commented on by hairdressers. They can easily be removed by shave excision or curettage under local anaesthetic.
12 Sebaceous Naevus
Sebaceous naevi are important because of their potential for malignant change, which has been reported in 10-15% of cases. The resultant malignant tumours are most commonly basal cell carcinomas. These usually develop in adulthood, although changes have occurred in children as young as five years.9
Men and women are affected equally. The lesions are often present at birth, although the characteristic appearance may not develop until puberty. Usually a solitary hairless patch on the scalp, or a velvety orange plaque on another area, such as the neck, is noticed at birth. Hormonal influences during puberty produce a verrucoid appearance, which can vary in size from 1 to 10cm in length. Larger lesions may be associated with multiple internal abnormalities.
The risk of malignant change means that excision tends to be the treatment of choice during puberty.
Photodynamic therapy with topical aminolevulinic acid is an alternative for those not amenable to surgery.
