VITILIGO- Differential diagnosis.

[gmohan]

What else might it be?

More common conditions that may be confused with vitiligo include:

Pityriasis versicolor (or tinea versicolor) — a superficial yeast infection that can cause loss of pigment, particularly in people with darker skin. It presents as small (less than 1 cm in diameter), round, pale macules, which are dry and slightly scaly when scratched. They are usually found on the upper trunk and chest. If vitiligo cannot be easily distinguished from pityriasis versicolor, consider using a Wood's lamp (if available) or taking skin scrapings for microscopy.
In pityriasis versicolor, hypopigmented areas may appear yellow under a Wood's lamp.

Post-inflammatory hypopigmentation — a partial loss of pigment following any inflammatory skin condition. It can be distinguished from vitiligo by being hypopigmented rather than depigmented, and by hypopigmentation being less obvious under a Wood's lamp. Conditions which are known to cause it include: eczema, psoriasis, scleroderma/systemic sclerosis, lupus erythematosus, lichen sclerosus, sarcoidosis, leprosy, mycosis fungoides (cutaneous T-cell lymphoma), and syphilis and other treponemal infections.

Pityriasis alba — variously defined as either a form of eczema or a form of post-inflammatory hypopigmentation following mild eczema. It is relatively common in children with darker skin, in whom multiple, poorly defined, hypopigmented, slightly scaly patches are seen on the face. In people with paler skin, it may only be visible in the summer when the normal skin tans. Hypopigmentation is less obvious under a Wood's lamp.

Idiopathic guttate hypomelanosis — a common condition, where numerous small (1–5 mm) white macules are distributed symmetrically on the trunk, arms, and legs. Individual lesions have well-defined borders and normal skin markings within them. In common with vitiligo, hypopigmentation is more obvious under a Wood's lamp.

Halo naevus — a mole with a regular, symmetrical halo of depigmentation around it. It is caused by an immunological reaction against melanocytes and, eventually, the mole disappears. They are benign, common in children, and occur more often (compared with the general population) in people who also have vitiligo.

Solar elastosis — a yellowish discolouration of the skin, caused by chronic sun damage, that is most obvious in skin creases and follicular openings on the face and neck. Both open and closed comedones may be seen.

Scarring — common in older people, those taking systemic steroids, and people who self-harm. In common with vitiligo, hypopigmentation is more obvious under a Wood's lamp.

Morphoea — a localized thickening of the dermis due to excess collagen. It is most common in women 20–40 years of age. Apparent hypopigmentation is less obvious under a Wood's lamp.

Lichen sclerosis and atrophicus — characterized by itchy, white atrophic plaques in the perineum and, rarely, on the trunk and limbs. Apparent hypopigmentation is less obvious under a Wood's lamp.

Progressive macular hypomelanosis — a common disorder in people of African or Afro–Caribbean origin. It is characterized by ill-defined macules on the trunk, often confluent in and around the midline, and rarely extending to the proximal extremities, head, or neck.

Melasma (chloasma) — hyperpigmentation of the face, most commonly seen in women taking combined oral contraceptives and in those who are pregnant. It may be confused with vitiligo because normally pigmented skin can appear hypopigmented in comparison with hyperpigmented skin.

Post-traumatic leukoderma — may occur after deep burns or after toxic epidermal necrolysis.

Less common conditions that may be confused with vitiligo include:

Piebaldism — an autosomal dominant condition in which there is an absence of melanocytes in affected areas of the skin. It usually presents at birth with depigmented areas near the midline on the front, typically a forelock of white hair. The patches remain unchanged throughout life, have a flat surface, and otherwise appear identical to vitiligo. In common with vitiligo, hypopigmentation is more obvious under a Wood's lamp.

Naevus anaemicus — a white patch due to localized vasoconstriction. It can be congenital or acquired. It may be seen in close association with a port wine stain, and is also seen temporarily following injection of adrenaline into the skin. The pallor disappears under a Wood's lamp.

Melanoma-associated depigmentation — occasionally, a halo of depigmentation is seen around a malignant melanoma. It differs from that seen in a benign halo naevus by being irregular and asymmetrical.

Chemical/occupational depigmentation — for example caused by phenolic/catecholic derivatives. Sources include adhesives, de-emulsifiers used in oil fields, deodorants, disinfectants, duplicating paper, formaldehyde resins, germicidal detergents, insecticides, latex gloves, motor oil additives, paints, photographic chemicals, plasticizers, printing ink, rubber antioxidants, soap antioxidants, synthetic oils, varnish, and lacquer resins.

Drug-induced depigmentation — from steroid injections and systemic drugs (for example, chloroquine, fluphenazine, phyostigmine, imatinib, and imiquimod).

Tuberous sclerosis — an inherited disease, characterized by ash-leaf shaped, depigmented macules on the trunk. Although it usually presents in early childhood, it is occasionally detected in older teenagers and young adults. Other dermatological features include facial angio-fibromas or periungual fibromas. It is important that it is diagnosed because internal organs can be affected. In common with vitiligo, hypopigmentation is more obvious under a Wood's lamp.

Albinism — a generalized loss of pigment that includes the eyes and is evident from birth. It is caused by defective manufacture of melanin.

Tuberculoid leprosy — can cause hypopigmented patches (usually one to five patches) with a raised red-copper coloured border. The patches can be distinguished from vitiligo in being anaesthetic, but there are usually other features to indicate the diagnosis (such as enlarged cutaneous nerves).

Incontentia pigmenti achromians of Ito (hypomelanosis of Ito) — characterized by depigmented whorls on the legs or trunk, usually in babies or small children. There may be associated disorders of the musculoskeletal system, eyes, teeth, and central nervous system. In common with vitiligo, hypopigmentation is more obvious under a Wood's lamp.

G Mohan.

[Badri]

Excellent dd for Vitiligo. It would be good if you can collect and post pictures of the different conditions.