Pediatric Dermatology Basics and Transient Phenomena

Basic And General Concepts For Paediatric Residents

Skin

• It has two layers: the outermost epidermis and below that is the dermis. The epidermis is divided into five layers of thick skin, like the palms and soles.

• Stratum basale- has germ cells, which constantly remove the upper layer, Stratum spinosum, Stratum granulosum-contains diamond shaped cells with keratohyalin and lamellar granules. Keratohyalin granules contain keratin precursors that eventually aggregate, crosslink, and form bundles. Stratum lucidum-thin layer under the stratum corneum. Stratum corneum- it is the topmost layer. It is also known as the cornified layer.  While in other places, the epidermis only has four layers, lacking the stratum lucidum. Below the epidermis of the skin is the dermis layer, further divided into the papillary dermis (the upper layer) and the reticular dermis (the lower layer).
• The epidermis, the outermost layer of skin, provides a waterproof barrier and creates our skin tone. The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands. The deeper subcutaneous tissue (hypodermis) comprises fat and connective tissue. The outermost skin cells are known as keratinocytes.

Ultrastructure Of Skin Biopsy Sample

• At the topmost, stratum corneum is present, which gives a basket-weave appearance. This layer has non-nucleated cells. Hence, it can be said that no living cells are present on the topmost layer, and these cells are integrated with the help of a protein known as filaggrin. Below the stratum corneum is the stratum granulosum, then the stratum spinosum and lastly, the stratum basale. Whenever Tinea infections (Fungal infections) happen, they affect the stratum corneum layer in children. Filaggrin is present in the stratum corneum, and under mutation, it can cause a disease like atopic dermatitis, also known as eczema.

Pilosebaceous Unit

• The hair follicle, hair shaft, sebaceous gland, and erectile muscle are collectively known as the pilosebaceous unit. The pilosebaceous unit is a complex, dynamic, 3-D structure site of unique biochemical, metabolic and immunological events.

Also Read: Infections of the Upper Airway- Common Cold and Sinusitis

Types Of Hair Present In Children

• Lanugo is very thin, soft, usually non-pigmented hair that covers the unborn baby. Appears before 36 weeks on preterm babies all over the body except palms & soles. Vellus hair is the short, fine, non-pigmented coarse body hair that grows in most places on the human body in both sexes. Appears between 36-45 weeks. Vellus hair is slightly coarser that Lanugo hair. Vellus hair is found in the face and the body (except scalp) in children. Terminal hair is longer, coarser, thicker, densely pigmented and darker. Fully developed hairs are present on the scalp and eyebrows of the postnatal baby. After puberty, they appear on the axilla, groin and the face and is replaced by the terminal hair.

Nomenclature Of Skin Lesions

• Non-palpable skin lesions where there is a colour change: Macule - flat lesion less than 1 cm, without elevation or depression. Patch - flat lesion greater than 1 cm, without elevation or depression.

Skin Elevation and Palpable forms are:

• Plaque - flat, elevated lesion, usually greater than 1 cm
• Papule - elevated, solid lesion less than 0.5cm
• Nodule - elevated, solid lesion greater than 0.5cm

Clear Fluid-Filled Lesion

• Vesicle - elevated, fluid-filled lesion, usually less than 0.5cm
• Bulla - elevated, fluid-filled lesion, usually greater than 0.5 cm

Pus Filled Lesion

• Pustule - elevated, pus-filled lesion, usually less than 1 cm
• Abscess- greater than 1 cm is known as an abscess.

Other Terms 

• Tumour- a large nodule of neoplastic origin

Wheal

• Urticaria is flat-topped palpable lesions due to dermal collection of edema fluid.  It may appear on one body part or be spread across large areas.  The rash is usually very itchy and ranges in size from a few millimetres to the size of a hand.  It is also known as urticarial lesions.

Lichenification

• It is a secondary skin lesion characterised by hyperpigmentation, thickening skin, and exaggerated skin lines. This occurs due to chronic inflammation and irritation. It is commonly found in atopic dermatitis.
• Erosion: superficial local epidermal loss. This heals without leaving a scar.

• Ulcers- Deep erosions involving the dermis. This heals by leaving a scar.

Benign Neonatal Dermatosis

Sebaceous Hyperplasia

• They appear as multiple, small, profuse, yellow-white papules. Sebaceous hyperplasia causes yellowish or flesh-coloured bumps on the skin. These bumps are shiny and usually on the face, especially the forehead, nose, cheeks and upper lip. They’re also small, usually between 2 and 4 millimetres wide, and painless. Sebaceous hyperplasia occurs when the sebaceous glands become enlarged with trapped sebum. This creates shiny bumps on the skin, especially on the face. No treatment is required in sebaceous glands.

Milia

• A milium cyst is a small (bigger than sebaceous hyperplasia), pearly white bump that typically appears on the nose, upper lips and cheeks. These cysts are often found in groups. Multiple cysts are called milia. They will be slightly larger than sebaceous hyperplasia. Size: 1 to 2 mm. They are a type of epithelial inclusion cyst. Milia occurs when keratin becomes trapped beneath the surface of the skin. Keratin is a strong protein in skin tissues, hair, and nail cells. No treatment is required in milia.

Milia v/s Miliaria 

• Miliaria is a common disorder of the eccrine sweat glands that often occurs in increased heat and humidity conditions. Miliaria is thought to be caused by blockage of the sweat ducts, which results in the leakage of eccrine sweat into the epidermis or dermis. It is of two types: Miliaria crystalline, also known as dew drops. They are asymptomatic. Miliaria rubra, which is also known as prickly heat (more common type).

Epstein Pearls

• One or multiple epithelial inclusion cyst present on had pallet (around the median raphe).  Epstein pearls are whitish-yellow cysts. These form on the gums and roof of the mouth in a new born baby. These are filled with keratinous materials. No treatment is required for Epstein pearls.

Bohn’s Nodules

• They are multiple epithelial inclusion cyst which appear as pearly white lesions on the gingiva in a neonate. They are filled with keratin-like material. Commonly seen in the upper gums when compared to that of the lower gums. Theories: They are a remnant of the odontogenic tissue present over the dental area. They are remnants of the minor salivary glands. Lesions that are keratin-filled cysts in the new-born’s mouth called Bohn's nodules. They are commonly found in the infant's mouth over the palate, buccal or lingual surfaces of the alveolar ridges, or occasionally along the hard and soft palate junction. No treatment is required.

Q. What are preputial Epstein pearls (PEPs)?

A. Epstein pearl-like lesion seen on the prepuce region in some male babies. No treatment is required.

Sucking Blisters

• Sucking blisters are due to natural neonatal sucking reflexes on the affected areas in utero. These sucking blisters occur at birth when the sucking movements are very aggressive in the uterus. These blisters are commonly found on the new-born’s arms, fingers, or any body part they can suck on. Usually seen during the 1^st week of life. No treatment is required. Association of sucking Blisters: Sucking pad.

The mid part of the lips will be swollen and slightly pale in colour.  Thickening and discolouration of the middle part of the (hyperkeratosis) lips often cause perioral erythema (not always present). Due to the rigorous ducking action of a child, this sucking pad is formed on the lips of the babies. Hyperkeratosis of the lips can be seen. No treatment is required.

Cutis Marmorata

• Comes with cold and disappears with warmth. It is a common vascular disorder that affects new-borns. When the new born is exposed to cold, a red and blue, lacy, reticulate pattern appears on the skin. This condition should be distinguished from Cutaneous Marmorata Telangiectasia Congenita (CMTC), a more permanent vascular anomaly that does not disappear with skin rewarming. Cutis Marmorata is considered a normal physiologic response of the new born to cold. The disorder is due to an immature neurological and vascular system. It consists of an alternating constriction and dilation of blood vessels, and it occurs most commonly in the hands and feet.

Cutis Marmorata Telangiectasia Congenita

• More intense, often segmental, persists despite warming. Associated with loss of dermal tissue, epidermal atrophy and ulceration.  Lowe limbs are more commonly affected than upper limbs. Atrophy of the affected limb may also be seen in some cases. Extracutaneous findings are present in 20-80% of the individuals. This may include abnormalities in the eye or in the CNS. Tends to fade slowly in 3 to 5 years.  No treatment is needed.

Harlequin Colour Change

• It is a self – limited vascular phenomenon. One half of the body is dark in colour and the other half will be pale in colour. Demonstrated by turning the child in side position. It is a cutaneous condition in new born babies characterised by momentary red colour changes in half the child. The dependant part becomes red in colour and the non-dependant part becomes pale. Improves on putting the child in supine position.   The reason for this condition is exaggerated autonomic dysfunction of cutaneous blood vessels. No treatment is available for this condition.

“Harlequins” you need to know!!!

• Harlequin ichthyosis is a pathological and severe genetic disorder affecting the skin. Infants with this condition are born prematurely, with very hard, thick skin covering most of their bodies. The skin forms large, diamond-shaped plates separated by deep cracks. Restricted chest movement can lead to breathing difficulties and respiratory failure in babies with harlequin ichthyosis.  Harlequin syndrome is a syndrome affecting the autonomic nervous system. The autonomic nervous system controls the body's natural processes, such as sweating, skin flushing, and pupils' response to stimuli. People with Harlequin syndrome are absent from sweating and skin flushing on one side of the body (unilateral), especially on the face, arms, and chest.

Nevus Simplex 

• It is also known as Salmon patch, a pink macule of capillary vascular malformation. It presents at birth as a pink or red patch and is most often observed on the nape of the neck, eyelid, or glabella. Sites: Forehead (glabella), upper eye lids, above upper lip, occiput and back of neck. It crosses the midline and can occur in 30-40% of new-borns.  As the age increases, this salmon patch disappears. The patch on the neck, however, persists. The characteristic that crosses the midline is important because it helps distinguish it from a port wine stain which does not cross the midline, is larger and unilateral. No treatment is needed.

Mongolian Spot 

• Dermal melanocytosis, also known as Mongolian spot or slate grey nevus, is one of many frequently encountered new born pigmented lesions.  It is a type of dermal melanocytosis, which presents as grey-blue areas of discolouration from birth or shortly after that. Congenital dermal melanocytosis is most commonly located in the lumbar, posterior thigh and sacral-gluteal region, followed by shoulders. They are not present on the face. Occurs due to increased melanin in the dermis due to the arrest of pigment producing cells in the dermis. It is a type of neural crest migration defect. Most cases start disappearing from 1 year of age and completely disappear by age 3-4. They never show malignant degeneration. Extensive Mongolian spots can be seen in various in born errors of metabolism like Hurler syndrome, Hunter syndrome, GMI gangliosides, NPD and mucolipidosis. They never show malignant degeneration.

Erythema Toxicum

• Seen in approximately 50% of term individuals. It begins on D2 of life. They may be in the form of only blotchy erythema or small white papules with surrounding erythema.  Never present on palms and soles. Child is asymptomatic. It disappears in 3 to 7 days. It is a common rash in full-term new-borns. It usually appears in the first few days after birth and fades within a week. Eosinophils are present in increased level. Up to half of all new-borns will have erythema toxicum. The rash can be on the baby's face, chest, arms, and legs. It's a blotchy red rash with small bumps led with fluid.  Eosinophils are present in the stains. Erythema toxicum, also called erythema toxicum neonatorum (ETN), doesn't cause any symptoms and goes away independently. So, no treatment is needed.

Transient Neonatal Pustular Melanosis

• It is an uncommon benign pustular condition in newborn infants. It is also known as transient neonatal pustular dermatosis and transient neonatal pustulosis. Any area can be involved, including the patient's forehead, posterior ears, chin, neck, upper chest, back, buttocks, abdomen, thighs, palms, and soles. Lesions can be either solitary or occur in clusters. They leave hyperpigmentation once they heal. Pustules disappear in 3 to 5 days. The hyperpigmentation may take up to 3 months to slowly disappear.  The pustules can rupture and crust, resolving within several days. The pigmented macules can have a collarette of scale. Histology: Neutrophils are present, no bacteria and occasional eosinophils can be seen. The pustules are present at birth and evolve; new lesions usually do not develop after birth. Treatment is not needed.

Infantile Acropustulosis

• It is a recurrent, self-limited, pruritic, vesiculopustular eruption of the palms and the soles in young children during the first 2-12 months of life. 10%: Neonates. 80%: 2 to 8 months. Morphology: appear as crops of grouped pustules which begin as erythematous papules. They last for a few days and disappear followed by new crop appearing in a few days. One crop lasts for 1 week and then there is a gap of around 2 weeks. This cycle continues till 2 years of age. Common sites: Palms and soles, sides of hands and feet. Treatment - Topical steroids are administered along with or without oral antihistamines.

Eosinophilic Pustular Folliculitis

Sometimes it occurs in new-born and other times, it occurs in infancy and older children. Most common site in children: Scalp. It is a recurrent skin disorder of unknown cause. It is also known as eosinophilic folliculitis. Skin biopsies of this disorder find eosinophils around hair follicles hence its name. Morphology: Appear in the form of multiple grouped pustules with folliculitis. Total eosinophilic count is always more than 5%; sometimes associated with raised TLC above 10 to 11000/mm³. Eosinophilic pustular folliculitis presents with itchy red or skin-coloured dome-shaped papules and pustules. It is characterised by raised eosinophils and increased total leukocyte count. Treatment- Topical steroids can be applied, and as age advances, it disappears.

Also Read: KEY POINTS AND RECOMMENDATIONS IN PEDIATRIC ADVANCED LIFE SUPPORT

Hope you found this blog helpful for your NEET SS dermatology preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.