The scalp is the skin that covers the head, and a thick scalp provides protection against damage from actinic damage. The hair follicle is a vital component. Production of hair is the primary and most important function of hair follicles. Even a slight change in the behavior of hair follicle can contribute to the development of hair disorders. The hair cycle is divided into the growth phase (also known as the anagen phase), regression phase ( also known as the catagen phase) and resting phase (also known as the telogen phase).
In the anagen phase, the metabolic activity among matrix keratinocytes that produce the hair fiber and hair root sheath is generally higher. The anagen phase leads to hair growth on the epidermis and anagen phase ends in the involution of a hair follicle, apoptosis, and terminal differentiation.
Catagen phase or regression phase is a short transitional phase of a cycle between the anagen phase and the telogen phase. It is the time of involution, and in this phase, the follicles undergo molecular and morphological changes that are associated with apoptosis. This phase lasts between two and four weeks.
The telogen phase is a phase that is expressed by relative rest in terms of activation and proliferation. This phase lasts for three to four months, and in this phase, the link between the lower part of the hair and follicular sac disappears. This leads to the fall out of hair.
Many types of disorders affect the scalp, and here is the list of three conditions that majorly impact an individual and requires immediate reaction and treatment.
Dermatophytosis is a common disease of body and scalp which is contagious and is caused by fungi known as dermatophytes. It belongs to the group of organisms that has an ability to break down the keratin into tissues such as hair, nails, and hooves. Usually, dermatophytes remain in superficial tissues such as hair and nails.
Dermatophytosis is also known as ringworm and it is defined as a fungal infection of the skin, scalp, feet, and nails. On the scalp, it is characterized by the small bump that is spread outwards leaving the scaly patches of temporary hair loss.
Infection on the scalp is troublesome and is it is left untreated, it can lead to permanent hair loss. On the skin, dermatophytosis is characterized as a flat ring-shaped rash that is usually reddish and can be scaly and itchy. Dermatophytosis can be spread from one person to another through direct contact.
It can also be spread indirectly through contact with articles that are contaminated or through contact with the surface that is contaminated by the fungus.
Scalp infection can be inflammatory or non-inflammatory. Inflammatory infection is characterized by boggy pustules and hair loss. It can cause the scalp to become scaly and red, Whereas, no-inflammatory infection is characterized by very little redness and pustules. The hair shaft can break the scalp and cause a black dot.
Kerion, also known as inflammatory tinea capitis is a disorder of the scalp that is caused by the fungi that belong to the group of dermatophytes. Clinically, kerion is defined as a painful condition that needs immediate treatment and it is characterized by the solitary and well-circumscribed inflammatory lesion with purulent discharge from multiple openings. The inflammation in the kerion can be caused due to an immunological mechanism.
Most often, due to purulent discharge, kerion is confused with bacterial abscesses. Kerion is a very painful condition, accompanied by a plaque and in order to prevent the complications, it requires an early diagnosis.
Undiagnosed kerion can lead to the occurrence of bacterial superinfection, folliculitis, and permanent alopecia. It appears as a solitary lesion and although it can occur at any part of the body, most commonly it appears on the scalp. Other sites on which kerion can occur include beards and eyebrows.
Kerion is associated with four types of histopathological patterns:
- Suppurative folliculitis – In this type of pattern, most hair follicles are in the catagen phase and it is characterized by a perifollicular inflammatory infiltrate with spongiosis and infiltrate of lymphocytes, plasma cells, and neutrophils.
- Suppurative folliculitis with suppurative dermatitis – In this type of pattern, hair follicles are in the catagen or telogen stage along with few disrupted follicles. It is characterized by a perifollicular and perivascular infiltrate of neutrophils along with edema in the papillary dermis.
- Suppurative folliculitis with suppurative and granulomatous dermatitis – In this type of pattern, there is a decreased number of hair follicles and it is characterized by infiltration of lymphocytes, neutrophils, plasma cell, and granulomatous reactions.
- Suppurative and granulomatous dermatitis with fibrosing dermatitis – It is characterized by inflammatory infiltrate of lymphocytes, neutrophils, and plasma cells along with the formation of granuloma, increased number of collagen fibers and absent hair follicles.
3. Telogen Effluvium
Telogen effluvium is a disorder of the scalp which is characterized as a thinning and shedding of the hair. It results from the early entry of hair in the telogen phase. Telogen effluvium leads to an abnormality of hair cycling, along with the excessive loss of telogen hair. Telogen effluvium can be classified as acute and chronic telogen effluvium.
In acute telogen effluvium, the shedding of hair can persist for around six months and it usually occurs two to three months after an event that triggers the symptoms of this disorder such as severe illness, childbirth, injury, major surgery or consumption of numerous medicines.
Normally, acute telogen effluvium is cured within six months but if the triggering events persist, it can lead to the development of chronic telogen effluvium.
In chronic telogen effluvium, the shedding of hair lasts for more than six months and it can last for years. There are many causes of chronic telogen effluvium and some of the cause of this chronic condition are thyroid disorders, iron deficiency anemia, chronic autoimmune disease, and malnutrition.
Chronic stress can also lead to the occurrence of chronic telogen effluvium and this is because chronic stress exerts a major impact on hair growth. This condition can involve the entire scalp.
Although telogen effluvium affects both the genders but numerous researchers suggest that women are more likely to experience chronic telogen effluvium as compared to men. Normally, in the scalp, the total number of hair follicles remains same throughout the life and as the duration of telogen does not vary, the proportion of follicles in the telogen is determined by the duration of anagen.
Tags: Scalp psoriasis, Scalp ringworm, Scalp problems